Gestational trophoblastic diseases – literature review and atypical case reports

Abstract

Gestational trophoblastic disease (GTD) arises from the abnormal development of trophoblastic tissue and encompasses a wide range of benign and malignant conditions. There is evidence that malignant transformation can occur in atypical areas of the placenta. A complete diagnosis of GTD involves assessing the signs and symptoms, with the most common being vaginal bleeding and pelvic-abdominal pain, alongside laboratory data and variations in human chorionic gonadotropin (hCG) levels. Imaging exploration, both local and distant, is critical for assessing tumor areas, utilizing various techniques such as ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)–CT. Furthermore, a detailed histopathological analysis is essential, which includes classical examination with Hematoxylin–Eosin (HE) staining to highlight the presence of abnormal villi or transformed trophoblasts. Immunohistochemical staining with antibodies like anti-cytokeratin 7 (CK7) marks tumor cells with trophoblastic origin, while anti-p57 is present in incomplete hydatidiform moles (HMs) and absent in complete HMs (CHMs). The tumor proliferation index, obtained by calculating the density of tumor cells undergoing division and immunolabeled with the anti-Ki67 antibody, along with the invasion into the myometrial structure among myocytes immunolabeled with anti-alpha-smooth muscle actin (α-SMA) antibody, helps establish a definitive diagnosis and classify GTD. Diagnosis remains a challenge even among expert gynecologists and pathologists. This study has gathered data from literature and analyzed the evolution of a series of atypical cases and the management strategies related to the diagnosis and therapeutic opportunities of GTD.

Introduction

Gestational trophoblastic disease (GTD) encompasses a series of tumors defined by abnormal trophoblastic proliferation, which includes both benign and malignant entities. Clinically, the symptoms can be similar: vaginal bleeding, pelvic pain; however, histologically, GTD is divided into hydatidiform diseases (which contain villi) and other trophoblastic tumors (without the presence of villi). Molar pregnancy (MP or hydatidiform mole – HM) can be classified as either a complete or partial mole and is usually considered the non-invasive form of GTD [1, 2]. Although HMs are generally regarded as benign, they are premalignant and can potentially become malignant and invasive [3, 4, 5].

Non-molar or malignant forms of GTD are termed gestational trophoblastic neoplasms (GTNs) and include invasive moles, choriocarcinoma, epithelioid trophoblastic tumor (ETT), and placental site trophoblastic tumor (PSTT) [6]. Malignant forms can appear weeks or years after an abortion or a molar or non-molar pregnancy (NMP), most commonly following an MP. GTN can metastasize and can be fatal if not correctly diagnosed and treated. Complete and correct treatment relies on a multidisciplinary team (MDT) that analyzes all aspects of these pathologies. An invasive mole occurs when abnormal trophoblastic cells deeply penetrate the uterine wall, potentially leading to complications. The rapid growth of abnormal tissue characterizes this pathology and can result in abnormal uterine bleeding [6].

Choriocarcinoma is a rare and aggressive neoplasm. The two significant subtypes of choriocarcinoma, namely gestational and non-gestational, have extremely different biological behaviors and prognoses. Choriocarcinoma predominantly occurs in women but can also appear in men, usually as part of a mixed germ cell tumor. ETT is a rare and distinctive subtype of GTN that arises from trophoblastic cells and is characterized by its epithelioid cell morphology. It has the potential to present as an aggressive tumor. This variant often occurs in women of reproductive age and may be associated with abnormal vaginal bleeding or a mass in the uterine cavity [1]. PSTT is another rare and distinct form of GTN that originates from the placental implantation site. Unlike more common trophoblastic tumors, PSTT tends to develop months or even years after a normal pregnancy, often following a term pregnancy or a MP. This tumor is characterized by slow growth and may manifest through irregular vaginal bleeding [1, 7].

Accurate diagnosis is based on both imaging evaluation, which can highlight the presence of abnormal placental villi or abnormal trophoblast, and histopathological (HP) assessment. Treatment can pose a challenge regarding fertility preservation, chemotherapy regimens, and subsequent monitoring [1].

Aim

The aim of this review was to emphasize the clinical, imaging, and HP characteristics of GTD and to demonstrate that there may be certain atypical variations reported in different presented cases.

Etiology

Trophoblastic cells provide the embryo with nutrients and participate in the formation of the fetal portion of the placenta. There are three types of trophoblastic cells: cytotrophoblasts (CTBs), syncytiotrophoblasts (SCTs), and intermediate trophoblasts (ITBs). Uncontrolled and abnormal proliferation of these cells causes GTD. Transformations occur at the level of CTBs and SCTs produce HM and choriocarcinoma. ITBs are associated with ETT and PSTT [5].

HMs are benign trophoblastic tumors that comprise approximately 80% of all GTDs. MPs are caused by abnormal gametogenesis and/or fertilization. These pregnancies are divided into complete and partial MPs. A complete MP (CMP) occurs when an enucleated egg is fertilized by either two sperm cells or a haploid sperm cell that then duplicates. Approximately 90% of complete moles have a karyotype of 46,XX, while 10% have a karyotype of 46,XY. The chromosomes have paternal origin; however, the mitochondrial deoxyribonucleic acid (DNA) is maternal [5]. Complete moles are the most common type of MP, do not contain fetal structures, and tend to result in elevated levels of human chorionic gonadotropin (hCG). Partial MPs are generally triploid (69,XXX; 69,XXY; or 69,XYY) as a result of the fertilization of a haploid egg by two sperm cells or the duplication of a haploid sperm cell during the fertilization of a haploid egg. There can also be diploid karyotypes, which result from the fertilization of an empty egg by two sperm cells. Both maternal and paternal DNA are expressed in partial moles [5]. Partial moles can also contain some fetal structures. Invasive moles occur specifically when these trophoblastic cells aggressively penetrate deep into the structure of the uterine wall. Choriocarcinoma develops from an abnormal trophoblastic population that undergoes hyperplasia and anaplasia, most commonly following a MP [5]. There are two forms of choriocarcinoma: gestational and non-gestational. Gestational choriocarcinoma (GC) occurs following HM, a normal pregnancy, or, most commonly, a miscarriage, while non-gestational choriocarcinomas (NGCs) arise from pluripotent germ cells [8]. The second subtype occurs in men or women in the gonadal structures or in midline structures with pluripotent germ cells [8].

The exact etiology of ETT remains somewhat elusive. ETT usually arises from trophoblastic cells involved in the development of the placenta during pregnancy. There is evidence suggesting a potential association with previous pregnancies, particularly those involving MP or GTD. PSTT is also rare and arises from the site of a previous pregnancy. Although the exact triggering factors for the development of PSTT are not well defined, it is believed that they involve abnormal proliferation of trophoblastic cells at the implantation site of the placenta [8].

Epidemiology

The incidence of HMs varies globally, with Southeast Asia and Japan having the highest estimated incidence at two in 1000 pregnancies. In the United States, they occur in approximately one in 600 therapeutic abortions and one in 1500 pregnancies. Proper management is important, as 15% to 20% of cases can transform malignantly and may require chemotherapy after evacuation [9].

Risk factors for HMs include patients at the onset of reproductive life or in perimenopause, ethnicity, and a previous history of an HM, suggesting genetic etiology. The risk of developing a CMP increase in women over 35 years old and those younger than 21, and it is 7.5 times higher in women over 40 years old. The risk of recurrence of a MP is approximately 1 [1]. Dietary factors, including diet deficient in beta-carotene (a precursor to vitamin A) and animal fats, as well as smoking, increase the risk of MP. It has been reported that a history of previous miscarriage confers a two to three times higher risk of developing a MP compared to women without a history of miscarriage [5]. Thus, after two MPs, the risk of having a third MP is 15–20% [10].

Approximately 50% of GTN cases occur after a MP, while 25% may develop after a spontaneous abortion, a pregnancy termination, or an ectopic pregnancy; the remaining 25% may result from a premature or term pregnancy. When GTN occurs after a MP, it is generally associated with invasive mole or choriocarcinoma, and rarely with ETT or PSTT. After a CMP, about 15% of patients will have persistent local disease with invasion, and 5% may develop metastatic disease. NGT after a NMP occurs at approximately 2–200 per 100 000 pregnancies and is usually a choriocarcinoma. GTN after pregnancy loss occurs in one in 15 000 cases; GTN after a term pregnancy occurs in one in 150 000 cases [11, 12, 13].

Choriocarcinoma is a very rare neoplasm, with variable incidence worldwide [1]. In the United States, choriocarcinoma occurs in approximately one in 20 000 to 40 000 pregnancies; 50% occur after term pregnancies, 25% after MPs, and 25% after other gestational events. In Europe, about one in 40 000 pregnant patients and one in 40 patients with HM will develop choriocarcinoma [14]. In Southeast Asia and Japan, 9.2 out of 40 000 pregnant women and 3.3 out of 40 patients with HM will subsequently develop choriocarcinoma [1]. In China, one in 2882 pregnant women will develop choriocarcinoma [14]. This correlates with an increased risk of developing choriocarcinoma in Asian, Native American, and Black women. Other risk factors include a previous complete HM (CHM) (with a 100 times higher risk), advanced age, long-term use of oral contraceptives, and blood group A [1].

Pathophysiology

The pathophysiology of HM involves the abnormal growth and development of placental tissue in the absence of a viable fetus. HM is associated with very edematous, vesicular immature placentas. A CMP leads to the development of only placental parts, while a partial MP also leads to the development of some or all fetal parts [15, 16]. Both types of MP occur through the supra-proliferation of chorionic villi. Several studies highlight a severe vasculogenic deficit in trophoblastic diseases, with significantly delayed angiogenesis at the onset of complete moles, progressive fluid accumulation, and subsequent formation of vesicular structures [17, 18, 19, 20, 21]. HMs and choriocarcinomas arise from the villous trophoblast, while PSTTs and ETTs originate from the ITB. CHMs are associated with aberrant budding, villous structures with trophoblastic hyperplasia, crumpled villous blood vessels, and stromal karyorrhectic debris. In contrast, early partial HMs show patchy villous hydrops, dispersed abnormally shaped erratic villi, patchy trophoblastic hyperplasia, and trophoblastic pseudo-inclusions. The karyotype encountered in CHMs is, in most cases, 46,XX and, less frequently, may be 46,XY. In the case of partial HMs, the karyotype can be 69,XXY, 69,XYY, or 69,XXX [15, 16]. Most result from the fertilization of a normal egg by two sperm cells (dispermic, 99%) and rarely from fertilization by one sperm cell followed by duplication of the paternal chromosomal content (monospermic, 1%). As a result, partial moles have a triploid genome, diandric and monogynic [22]. Rarely, partial HMs have been reported with three sets of paternal chromosomes and one set of maternal origin [23].

The correct differential diagnosis between a non-molar spontaneous abortion and a partial or CHM can be made using in situ hybridization techniques, flow cytometry (FC), or other molecular investigations [24]. Rarely, an MP can coexist with a normal pregnancy. The diagnosis is usually made through ultrasound (US) examination. Despite the high risk of spontaneous abortion, in approximately 40–60% of cases, it results in live births. The risk of GTN in such a situation is 27–46%, while in a single MP, the risk of developing GTN is 15–20% [24].

The invasive hydatidiform mole (IHM) frequently develops from complete moles [25] and more rarely from partial moles [26]. Choriocarcinomas are malignant epithelial tumors that secrete hCG, characterized by central necrosis and a biphasic structure. Intraplacental choriocarcinomas (ICs) are likely responsible for metastatic disease following term pregnancies. Most neonatal choriocarcinomas result from metastatic spread from ICs. Regarding the pathogenesis of choriocarcinoma, studies have shown that CTB cells function as stem cells and undergo malignant transformations. The neoplastic CTB subsequently differentiates into ITB and SCT [27].

ETTs, the rarest types of GTN, present nests of tumor cells composed of fairly uniform mononucleated ITB. These nests are interspersed among necrotic debris and hyaline degeneration. ETTs can appear as discrete hemorrhagic, solid, or cystic lesions [28, 29]. PSTTs are malignant tumors formed from uterine lesions with less hemorrhage, necrosis, and lower concentrations of hCG than choriocarcinomas [30].

Clinical features

CHM is associated with abnormal vaginal bleeding (“prune juice” appearance) during the first trimester, and US shows the presence of ovarian theca lutein cysts >6 cm in diameter, with the uterus typically significantly enlarged for gestational age. Serologically, the level of hCG is very high, correlating with gestational age, typically greater than 100 000 international units (IU). Medical complications such as pregnancy-induced hypertension, elevated liver function tests, and proteinuria (associated with preeclampsia), hyperthyroidism, hyperemesis gravidarum, anemia, and thrombocytopenia may also be associated [1].

Partial mole is frequently associated with spontaneous abortion, vaginal bleeding, anemia, and an enlarged uterus for gestational age; in general, symptoms are less pronounced compared to complete mole [31]. Serologically, β-hCG, inhibin A, and activin A may be elevated. Elevated β-hCG levels >100 000 mIU/mL are present in less than 10% of patients [1, 31, 32].

IHM is clinically associated with vaginal bleeding and persistent serum hCG after the evacuation of HM [33].

Choriocarcinoma is clinically associated with vaginal bleeding. It may also initially present with metastatic disease, especially after NMPs, in the lungs, where it is associated with symptoms such as dyspnea and hemoptysis, in the lower genital tract as localized nodules in the vulva, vagina, or cervix, in the liver when there is a change in liver function or intra-abdominal hemorrhage, and in the brain, associated with neurological symptoms such as seizures or altered mental status [34]. Significantly elevated hCG is a reliable marker of disease that reflects tumor pregnancy; therefore, it is used for diagnosis, monitoring, evaluating the response to therapy, and screening for recurrences [6, 34].

In the case of ETT, menometrorrhagia is the most common symptom, but amenorrhea may also occur [35]. The latency period can vary between two months and 15 years, with an average of 6.2 years; the median interval is 32 months [35, 36].

PSTT is frequently associated with amenorrhea, abnormal bleeding, and an enlarged uterus [37]. Virilization phenomena, nephrotic syndrome, and erythrocytosis may occur [38]. In 66% of cases, it arises after a term pregnancy, with a median latency of 12–18 months (ranging from a few months to 20 years) [39]. It occasionally occurs following spontaneous abortions and HM (10–50% of cases) [40]. At presentation, over 80% of cases fall into stage 1 of the Fédération Internationale de Gynécologie et d’Obstétrique (International Federation of Gynecology and Obstetrics; FIGO) [40]. Metastasis or recurrence may occur in 25–30% of patients [41]. In this pathology, the mortality rate is associated with 6.5–27% [42]. Regarding laboratory tests, serum levels of β-hCG are generally low (<1000 mIU/mL), but mild to moderate elevation of serum hCG (5–26 000 mIU/mL, average: 680 mIU/mL) may occur in 80% of cases [37, 39, 41].

Imaging of gestational trophoblastic disease

In the case of CHM, US evaluation reveals the following aspects: a heterogeneous, hyperechoic placental mass in the uterine cavity with multiple anechoic spaces (“snowstorm appearance”), the embryo or fetus is absent, amniotic fluid is not present, and ovarian theca lutein cysts larger than 6 cm are frequently observed [24]. Magnetic resonance imaging (MRI) plays a role in the evaluation of HM with atypical presentations [43, 44, 45]. Although HMs are diagnosed early worldwide, in developing countries, there are still patients diagnosed after the first trimester of pregnancy when complications associated with MP arise [46]. Chest X-ray and computed tomography (CT) can be used to assess complications of HM, especially when patients report respiratory distress [47, 48].

Regarding partial HM, the US diagnosis is more challenging because it mimics a normal early pregnancy with a present embryo or fetus. Suspicion on US arises towards the end of the first trimester when a thickened placenta is visualized [49]. Additionally, intrauterine growth restriction, fetal structural anomalies, and placental cystic changes can be observed during the second trimester of pregnancy [50]. Hydropic abortion can also mimic partial HM, especially when a visible embryo is present, at which point hCG levels are an important tool for establishing the correct diagnosis. Theca-lutein cysts can also be present when hCG levels are high [51, 52, 53].

Multiple pregnancies with CHM and a coexisting normal fetus are rarely encountered, with an incidence of 1:20 000–100 000 pregnancies [54, 55], and US is the initial tool used to evaluate these pregnancies. Thus, two distinct placental images are present: one with a normal appearance and a fetus without structural anomalies, and the other with molar changes. US diagnosis is not always able to confirm this diagnosis, at which point MRI examination is necessary to help differentiate the two distinct placentas and determine the interface with the myometrium [43, 44].

US imaging in GTN can present a variety of characteristics: the presence of a hyperechoic, hypoechoic, or heterogeneous myometrial mass, often lacking a clear interface with the endometrium; other times, cystic areas appear in the myometrium resembling HM invasion. However, there are no sonographic characteristics that can clearly differentiate the histological types of GTN [56, 57]. In cases with suggestive US images for GTN and low levels of hCG, there may be suspicion of PSTT or ETT [24, 29]. Doppler US can help in evaluating GTN, as it is a group of highly vascularized tumors [56, 58]. Studies have shown three different vascular patterns of GTN: diffuse, lacunar, and compact. The diffuse pattern is characterized by nonspecific myometrial vascularization, the lacunar pattern presents vascular lacunae within a complex myometrial mass with turbulent flow, and the compact pattern is observed in patients with a hyperechoic mass with peripheral vascularization, low resistance, and a central avascular area [59]. Doppler velocimetry of the uterine artery before the initiation of chemotherapy has been correlated with GTN resistance to Methotrexate. A pulsatility index (PI) of less than 1.0 appears to be a risk factor for resistance to Methotrexate in low-risk GTN [29, 57]. There is also evidence that lower Doppler velocity indices of the uterine artery before and after surgical evacuation of HM are predictive for GTN [60]. CT is used for evaluating distant metastases, as this imaging modality is not specific for uterine analysis, even after the administration of contrast material. On MRI, GTN presents as irregular uterine masses, isointense (on T1-weighted images) and hyperintense (on T2-weighted images), distorting the endomyometrial junction area and showing intense signal after gadolinium administration. Since GTN lesions are highly vascularized tumors, numerous vessels can be seen in the myometrium and around the uterus. MRI evaluation is not absolutely necessary, as there are no specific characteristics that distinguish the types of GTN. Therefore, clinical information and laboratory tests are essential for diagnosing GTN. MRI is useful for assessing the primary tumor and local invasive disease prior to surgical treatment, as this modality is superior to US and CT in evaluating parameters, the vagina, pelvis, and lymph nodes [58, 59, 61]. The role of positron emission tomography (PET)–CT is not yet well defined in the management of patients with GTN, as experience with the use of this modality in this group of diseases is limited. This imaging modality may be helpful, especially in patients with recurrent disease. Abnormal imaging findings seen in GTN may persist for months after treatment completion; therefore, it is not routinely performed during follow-up. Imaging follow-up is necessary if there is suspicion of chemoresistance or disease recurrence, usually associated with increased or stabilized hCG levels [62, 63].

Morphopathological features of gestational trophoblastic disease types

Complete hydatidiform moles

Macroscopically, the placenta is transformed, voluminous, weighing over 200 g, with hydropic changes in all villi, which appear as semi-transparent vesicles ranging in size from 1–30 mm, resembling “a bunch of grapes” developed from the chorionic villi. Normal placental structures or fetal parts are absent [15, 16, 64].

Microscopically, hydropic and deformed chorionic villi appear, forming “cisterns” that contain stromal fluid; fetal tissue and capillary villi are absent. The mature vascular network is otherwise present, positive for cluster of differentiation (CD)31, with dysmorphic features such as a complete lack of lumen, a certain degree of cytological atypia, many cells being mitotically active, positive for immunostaining with anti-Ki67 antibody; central cisterns and trophoblastic hyperplasia are also present. Stromal changes such as the appearance of stromal mucin (MUC) and apoptosis occur early and can aid in diagnosis [1, 15, 16, 65].

CHM presents positive stains for p53 (85%, compared with 60.9% in partial moles), hCG, placental alkaline phosphatase (PLAP), and human placental lactogen (hPL), and negative stains for p57, which represents a cyclin-dependent kinase (CDK) inhibitor protein, the product of the paternally imprinted, maternally expressed CDKN1C (p57KIP2) gene located on chromosome 11p15.5. Complete mole does not have maternal genes [66].

Partial hydatidiform mole

Macroscopically, immature placental tissue is present, mixed with vesicles that tend to be smaller and less numerous than those of a CHM. The fetal parts and the gestational sac may be present [67].

Microscopically, there is heterogeneity in the size of the villi with two discrete populations (large, hydropic villi and small, fibrotic villi). The enlarged villi are irregularly shaped, with scalloped margins and secondary trophoblastic pseudoinclusions. Cyst formation may be observed in the enlarged villi. Mild circumferential trophoblastic hyperplasia may also be encountered. Fetal parts and nucleated red blood cells may also be present. The presence of at least three of the above histological characteristics of partial mole correlates with triploidy on fluorescence in situ hybridization (FISH) and FC analysis [68].

Partial HM presents positive stains for p57, with nuclear expression in at least 10% of the stromal villous cells and CTBs. Partial HM cannot be distinguished from non-molar specimens since both have maternal DNA [69]. Rare cases of incomplete HM may present as p57-negative due to the loss of the maternal copy of chromosome 11; genotypic analysis would confirm diandric triploidy [70].

Invasive hydatidiform mole

Macroscopically, an erosive and hemorrhagic lesion is present in the myometrium. The invasion can be superficial or complete, and it may even perforate the uterus and invade the periuterine structures. Hydropic structures may also be present [71].

Microscopically, the presence of molar villi with associated trophoblastic structures penetrating into the myometrium, at the level of the uterine or extrauterine vessels, is observed. Typically, the morphological characteristics of complete or partial HM are noted in the invasive component; the villi are usually less hydropic, but they may also exhibit prominent hydropic changes with increased trophoblastic hyperplasia. Metastatic HMs are most commonly complete [71].

IHM presents positive stains for p57 at the nuclear level in the villous CTB and villous stromal cells in invasive partial moles, and negative stains in the villous CTB and villous stromal cells in invasive CHM [72].

Choriocarcinoma

Macroscopically, it appears as a dark red, solid, friable tumor formation with areas of hemorrhage and necrosis. IC may be present as a subtle lesion in general and is usually confused with a placental infarct. The most common site of occurrence is represented by the endomyometrium [15, 16].

Microscopically, solid sheets of atypical SCT, CTB, and ITB are observed. The chorionic villi are absent, except in IC, where the tumor is surrounded by villi. The tumor cells recapitulate chorionic villous trophoblasts of various types and are arranged in biphasic to triphasic growth patterns. Additionally, sheets or chords of mononuclear tumor cells are surrounded by layers of multinucleated SCTs. Tumor thrombi in lymphovascular structures may be present [72]. Mitotic activity is very high, and necrosis and intratumoral hemorrhage occur. It can also be associated with other types of trophoblastic diseases such as ETT or PSTT [73, 74].

Choriocarcinoma presents positive stains for pan-cytokeratin (CK) AE1/AE3, CK7 in all cells, and Ki67-positive in more than 90% of the cells. The SCT is positive for hCG and inhibin; the CTB is positive for spalt like transcription factor 4 (SALL4), nuclear β-catenin, and for subtype 3 of the GATA family of transcription factors (GATA3); the ITB is focally positive for p63, hPL, melanoma cell adhesion molecule (Mel-CAM, CD146), inhibin, GATA3, and transmembrane or membrane-bound mucin 4 (MUC4). Choriocarcinoma shows negative stains for tumor suppressor protein 16 (p16) [75].

Epithelioid trophoblastic tumor

Macroscopically, ETT presents as an expansible mass with a whitish-yellow, fleshy appearance, solid on the cut surface, invading the underlying stroma. Areas of necrosis and hemorrhage may also be present. Ulceration and fistula formation occur frequently [35].

Microscopically, nests and cords of medium-sized epithelioid cells are present, with eosinophilic to clear cytoplasm, distinct cellular borders, and round nuclei with small nucleoli. Cytological atypia is moderate, and mitosis is frequent. These cells are arranged in a hyaline matrix associated with geographic necrosis, apoptotic cells, focal calcifications, and scattered decidualized stromal cells at the periphery. Eosinophilic material-resembling hyaline is characteristically present in the center of some tumor nests, simulating keratin formation. A well-circumscribed tumor border is characteristic. Unique histological features include benign decidualized stromal cells scattered at the tumor periphery, frequent calcification, and ETT tumor cells frequently colonizing the surface of the mucosa or the glandular epithelium of the cervix and endometrium, which may simulate high-grade squamous intraepithelial lesions or squamous epithelium [66, 76].

ETT presents positive stains for p63, inhibin-alpha, cyclin E, GATA3, CD10, epithelial membrane antigen (EMA), CK7, CK18, pan-CK AE1/AE3, and a Ki67 labeling index >10% (mean: 18%, range: 10–25%) [49]. Additionally, ETT shows negative stains for hCG, PLAP, hPL, Mel-CAM, and for estrogen receptor (ER) and progesterone receptor (PR) [77, 78].

Placental site trophoblastic tumor

Macroscopically, PSTT appears as a well-circumscribed nodular mass, up to 10 cm in size, which may be polypoid and project into the uterine cavity or may predominantly involve the myometrium. The cut surface is usually solid, fleshy, and white-brown to light yellow in color, containing only focal areas of hemorrhage or necrosis. Deep invasion of the myometrium is observed in 50% of cases. It may extend to the uterine serosa in 10% of cases and, in rare cases, to the adnexal structures, including the broad ligament [39].

Microscopically, it appears as aggregates or sheets of large, polyhedral to round, predominantly mononucleated cells composed of implantation site ITB cells. Multinucleated trophoblastic cells scattered at the implantation site are common. Tumor cells often aggregate into confluent sheets; at the periphery, trophoblastic cells invade either singly or in cords and nests into the myometrium, separating individual muscle fibers and groups of fibers. Vascular invasion is often present, where tumor cells penetrate the walls of the myometrial vessels and transform them, giving a unique appearance to human solid tumors and are diagnostic for PSTT. Cytologically, the cells have abundant amphophilic cytoplasm, occasionally eosinophilic or clear. The nuclei of the tumor cells are pleomorphic, and nuclear atypia is generally pronounced, with frequent large, convoluted nuclei and marked hyperchromasia. Most tumors have a low number of mitoses, with 1 to 2 mitoses/mm2 (equivalent to 2 to 4 mitoses per 10 high-power fields of 0.5 mm in diameter and 0.2 mm2 in area) [39]. The Arias-Stella reaction appears at the decidual level in the adjacent, unaffected endometrium; villi are almost never identified, and tumor necrosis may be present [71].

PSTT presents positive stains for hPL, CK, MUC4, Mel-CAM, CD10, GATA3, and Ki67 expressed in 8–20% of cells, as well as for programmed death-ligand 1 (PD-L1) [79], and negative stains for p63, hCG, inhibin, and PLAP [79].

Positive and differential diagnosis

The positive diagnosis for HM is based on clinical data, laboratory findings represented by elevated hCG levels, the aforementioned US aspects, as well as the evacuation of the MP through aspirational curettage and the submission of tissue fragments for HP evaluation, which provides a definitive diagnosis. The differential diagnosis between CHM, partial HM, and hydropic abortion is made through HP examination [80]. An algorithmic approach has been proposed, along with immunohistochemistry for p57, utilizing morphological assessment to triage cases for genetic analysis. Thus, p57-negative cases with molar morphology would be diagnosed as CHM without genotypic analysis, and all p57-positive cases would undergo genotypic analysis. The differential diagnosis of CHM is made with partial HM, where fetal or embryonic tissue may be present, chorionic villi show focal edema, scalloping, and prominent stromal trophoblastic inclusions, the villous circulation is functional, and focal trophoblastic hyperplasia and atypia are minimal. In the case of partial HM, p57 is positive in the villous stromal and CTB cells, and cytogenetic studies show diandric triploidy (69XXX, 69XXY); with hydropic abortion where polarized trophoblastic proliferation occurs, trophoblastic atypias are absent, showing only slightly enlarged and edematous villi that occasionally form cisterns. Hydropic abortion is associated with biparental diploidy; with abnormal villous morphology, possibly linked to the presence of other genetic anomalies, generally aneuploidies, with complex karyotypes (trisomy with combined monosomy, tetraploidy); and with placental mesenchymal dysplasia, where the fetus is present and may have normal growth, while trophoblastic proliferation is absent [81].

The differential diagnosis of partial HM is made with CHM, where p57 is negative and androgenetic diploidy appears through molecular testing; with early complete mole (less than 12 weeks): without the presence of an embryo, which may have a morphological overlap with partial HM, as the molar characteristics are not well-developed (the villi are smaller, the cisterns and cavities are not well-developed, a certain degree of trophoblastic proliferation and atypia is present); with well-developed complete mole that does not present fetal or embryonic structure, but has a population of villi with extensive hydatidiform transformation, more trophoblastic hyperplasia, and cellular atypia; and with hydropic spontaneous abortion where only slightly enlarged and edematous villi are present, with occasional formation of cisterns, and the tissue is usually less voluminous than in partial HM. It presents biparental diploidy through molecular testing; with Beckwith–Wiedemann syndrome: where the placenta is associated with severe anomalies, edema, enlarged villi, centrally cavitated stem villi, scalloping, and SCT hyperplasia should be absent. This syndrome is associated with diploidy [82]; with mosaic/chimeric conceptions where a spectrum of morphological changes may be present, some of which may suggest a IHM, and p57 is useful in identifying androgenetic tissue (which is p57-negative), while FISH and genotyping are necessary for complete characterization [83]; with non-molar placentas with cytogenetic abnormalities, such as trisomies, where abnormal villi suggestive of incomplete HM may be present. Distinction based solely on morphological criteria is difficult and poorly reproducible, and genetic testing is necessary to identify the cytogenetic anomaly [84]; with twin gestation with complete mole and coexisting fetus, a rare situation that usually presents two villous populations, which may be confused with partial HM. The molar villi exhibit typical characteristics for CHM: atypia, cavitation, marked trophoblastic proliferation, while the fetus has a normal karyotype and is normally developed. p57 will be absent only in the molar villi [85, 86]; and with placental mesenchymal dysplasia: a rare condition that occurs more frequently in mature placental structures, with an appearance of placentomegaly, massive hydrops, cystic dilation, and vesicle formation, with abnormally thick villous vessels with fibromuscular hypertrophy, and apparently normal terminal villi, without trophoblastic hyperplasia or atypia. In this situation, both the placenta and fetus have a normal karyotype, with p57-positive in the CTB but with p57-negative in the villous stroma [87, 88].

IHM is suspected radiologically, but it is rarely diagnosed before evacuation or surgical intervention [33]. The differential diagnosis is made with choriocarcinoma, which also presents high hCG levels, atypical cytology, and more pronounced proliferation, in addition to a biphasic pattern of atypical SCT and CTB. The absence of villi favors choriocarcinoma, except in rare cases of GC [83]. Differential diagnosis can also be made with placenta accreta, which presents normal villous structure invading the myometrium without an intermediate decidual layer. The villi do not exhibit hydropic changes and do not show trophoblastic hyperplasia or atypia. Accreta is generally diagnosed later in pregnancy compared to MPs, which are diagnosed early [83].

The diagnosis of choriocarcinoma combines persistently elevated hCG levels with characteristic imaging findings. Generally, HP examination confirms the presence of choriocarcinoma; however, it is rarely used solely for diagnostic purposes and is more commonly employed for postoperative confirmation [34]. The differential diagnosis is made with PSTT, which consists of ITB at the implantation site, characterized by a single population of mononuclear cells with eosinophilic and amphophilic cytoplasm, being diffusely positive for hPL and Mel-CAM, and focally positive for hCG; with ETT, where there is chorionic-type ITB, characterized by a single population of mononuclear cells with eosinophilic to clear cytoplasm, with positivity for p63, focal for hCG, Mel-CAM, and hPL; with IHM, HM, or with early pregnancy loss where villi indicate IHM, MP, or early pregnancy loss. Nuclear atypia may be present in IHM, MP, and early pregnancy loss. However, marked extensive cytological atypia favors the diagnosis of choriocarcinoma. The differential diagnosis can be challenging, especially when the analyzed tissue is quantitatively limited. The diagnosis of atypical trophoblastic proliferation may be made, as some cases of early choriocarcinoma cannot be histologically differentiated from atypical proliferations associated with IHM, HM, or early pregnancy loss. Additionally, differential diagnosis can also be made with NGC, which is morphologically and immunohistochemically identical to GC. The presence of ovarian tumors before puberty favors NGC. Furthermore, mixed endometrial tumors present in menopause, with non-trophoblastic carcinomatous components, and extrauterine tumors without a primary uterine origin favor NGC. A definitive diagnosis is made after a short tandem repeat (STR) analysis. NGC has identical alleles to those of the patient and the absence of alleles from the partner [34].

The diagnosis of ETT is made using imaging evaluation correlated with clinical characteristics, but it is confirmed through HP diagnosis obtained via biopsy or tumor resection. The differential diagnosis is made with cervical squamous cell carcinoma (CSCC), where true keratin formation is present, cell bridges appear, and there are no associated decidualized stromal cells at the periphery, while hCG is not elevated. CSCC is not positive for trophoblastic differentiation markers; with endometrioid carcinoma, where trophoblastic differentiation markers are negative, p63 is negative, and there is an association with mismatch repair protein loss, while ER and PR are present; with placental site nodule (PSN), where single or multiple, well-circumscribed nodules usually <5 mm are observed, and mitotic activity is very low (Ki67 proliferation index <8%); with atypical PSN where the nodule size is larger than PSN (>5 mm to 10 mm), with increased cellularity, marked nuclear atypia, moderately increased mitotic activity, and Ki67 proliferation index between 8% and 10%. This pathology may express cyclin E; with PSTT, where an infiltrative growth pattern is observed, the reaction to p63 is negative, but there is diffuse expression of hPL; with choriocarcinoma, where diffuse hemorrhages, marked cytological atypia, and a dimorphic trophoblastic population are present. In this pathology, there is diffuse expression of hCG, and the cellular proliferation index is high, with Ki67 >70% [89].

In the case of PSTT, a definitive diagnosis is made through biopsy or hysterectomy, and the differential diagnosis is made with exaggerated placental site (EPS), where there is exuberant infiltration of the ITB implantation site, characterized by a formation lacking mitotic activity (Ki67 ~0%), composed of ITB cells separated by hyaline structures. This pathology typically appears intercalated with decidua and chorionic villi, containing a large number of multinucleated trophoblastic cells; with ETT, which has an expansive nodular growth and the presence of fibrillar hyaline material, extensive geographic necrosis, calcification, and absence of vascular invasion. ETT is positive for p63, PLAP, and inhibin; with choriocarcinoma, which appears as a trimorphic proliferation of SCT, CTB, and ITB, with strong expression of β-hCG, elevated serum levels of hCG (1000 mIU/mL to 1 000 000 mIU/mL), and a high cellular proliferation index (Ki67-positive >40% of cells); with CSCC, where there are atypical basaloid cells with a high nuclear/cytoplasmic ratio, nuclear hyperchromasia, positivity for p16, human papillomavirus (HPV), and negative reactions for hPL, CD146, MUC4, along with a high cellular proliferation index (Ki67-positive); with poorly differentiated carcinoma where there are various glandular and epithelial differentiations (squamous, tubal); with epithelioid smooth muscle tumors, characterized by a fascicular morphological pattern, positive for smooth muscle actin (SMA), desmin, and negative for hPL, CD146; and with metastatic melanoma, where large nucleoli are present, and the tumor tissue is diffusely positive for melanoma markers: human melanoma black (HMB45), melanocyte-specific cytoplasmic protein (Melan-A), and S100 [90].

Treatment and follow-up

In cases where an MP is suspected based on US results and elevated hCG levels, an evaluation for the possibility of medical complications such as electrolyte imbalances caused by hyperemesis, anemia, hyperthyroidism, and preeclampsia should be conducted. After a thorough evaluation, the method of evacuation is decided. Surgical uterine evacuation through dilation and suction evacuation is the cornerstone of management for complete and partial HMs, regardless of the size of the uterus [91]. US guidance is recommended when the uterus is enlarged to ensure complete evacuation. Anti-D immunoglobulin should be administered after the procedure if the patient is Rh-negative [92]. Hysterectomy is an option for patients who have completed their reproductive years. Hysterectomy reduces the risk of developing GTN, which is >50% in women over 40 years old compared to aspiration evacuation and may eliminate the need for subsequent chemotherapy. Therefore, hysterectomy may be particularly reasonable for patients over 40 years of age with CHMs [93, 94]. There are studies that have shown that the use of uterotonics may increase the risk of metastatic disease [1, 91].

The administration of prophylactic chemotherapy after the evacuation of CHMs with high risk reduces the incidence of GTN. When there is significant concern about the reliability or availability of hCG follow-up, some clinicians consider chemoprophylaxis for patients with CHM at high risk [92]. All patients diagnosed with MP are recommended to have periodic monitoring of serum hCG levels after evacuation to assess the presence of subsequently arising GTN. The guidelines from the American College of Obstetricians and Gynecologists (ACOG) recommend the following hCG monitoring protocol: weekly measurement until undetectable for three weeks, then monthly for six months. If hCG remains undetectable for six months, the patient may resume attempts to conceive [92]. Following the evacuation of a complete or partial MP, if hCG levels rise or remain elevated for several weeks, the patient is classified as having GTN. The diagnosis of post-molar GTN is based on the criteria from the FIGO: hCG levels stabilize (remain within ±10% of the previous result) in four measurements taken over three weeks, or hCG levels increase by >10% in three measurements over two weeks, or if serum hCG is detectable for more than six months after molar evacuation [2, 95]. A low risk choriocarcinoma, with a cumulative prognostic score <7 (see the staging section below) and stage I to III can be treated with a single chemotherapeutic agent: Methotrexate or Dactinomycin. High-risk disease, with a cumulative prognostic score >7 (see the staging section below) and stage II to IV, is treated with polychemotherapy, adjuvant radiotherapy, and surgery [96]. In these situations, after treatment and normalization of hCG, monitored monthly for one year and with gynecological consultations twice during this period, if a subsequent pregnancy occurs, a pelvic US should be performed in the first trimester to confirm an intrauterine location due to the low risk of recurrent choriocarcinoma. The placenta should be histologically examined afterwards to exclude recurrence [96]. In cases associated with chemoresistance, severe disease, or when fertility preservation is not desired, hysterectomy is the most common treatment option [5]. Additionally, it has been shown that Pembrolizumab is one of the medications used in this situation [97].

The initial treatment for non-metastatic PSTT or ETT consists of hysterectomy and salpingectomy, with or without lymph node biopsy. In cases of metastatic PSTT or ETT, hysterectomy, salpingectomy, and resection of metastatic disease are recommended, followed by platinum-based chemotherapy [98]. In the case of persistent elevated hCG levels, a second aspirational curettage may be performed if there is no increased risk of uterine perforation or hemorrhage [5]. A multicenter study conducted in Canada in 2016 demonstrated that the second aspirational curettage cured 40% of patients without complications when used as initial treatment for low-risk, non-metastatic GTN [98].

Staging

Staging of GTN is based on the location and extent of the tumor, as follows: stage I of the disease is confined to the uterus, stage II involves direct extension or metastasis to other genital structures, stage III is identified by pulmonary metastases, and stage IV includes distant non-pulmonary metastases. There are three main systems used for the staging and classification of GTD: the National Institutes of Health (NIH) clinical classification system and the World Health Organization (WHO) prognostic scoring system: the FIGO Staging and Risk Factor Scoring System, which was revised and updated in 2000 [99, 100].

The clinical classification system is widely used in the United States. This system differentiates patients based on the presence or absence of metastatic disease, as all patients with non-metastatic disease can be cured with initial chemotherapy using a single agent. Patients with metastatic disease are further subdivided based on the presence or absence of risk factors associated with the response to initial single-agent chemotherapy. Patients without high-risk clinical factors are likely to benefit from initial single-agent therapy and are labeled as having metastatic GTD with a good prognosis; conversely, patients with a single high-risk clinical factor are labeled as having metastatic GTD with poor prognosis. These patients with an unfavorable prognosis have an increased risk of single-agent chemotherapy failure and death if treated with monotherapy, followed by polychemotherapy regimens. The WHO prognostic scoring system provides accurate information. A 97% correlation of risk categorization has been demonstrated between the original WHO (1983) and FIGO 2000 systems [101]. The current FIGO prognostic scoring system has been adapted from the WHO Classification. The FIGO prognostic score is based on individual risk factors that have been shown to predict GTN resistance to single-agent chemotherapy. For patients with PSTT or ETT, only the stage will be provided. A risk factor score is not applicable in these cases. Low-risk GTD has a total prognostic score <7. High-risk GTD has a total prognostic score of ≥7 (Table 1).

Table 1.

FIGO prognostic score (modified from NCCN Guidelines for Gestational Trophoblastic Disease 2022) [101]

Prognostic factor	Score
0	1	2	4
Age [years]	<40	≥ 40	–	–
Antecedent pregnancy	Molar pregnancy	Abortion	Term pregnancy	–
Interval from index pregnancy [months]	<4	4–6	7–12	>12
Pretreatment hCG [mIU/mL]	<1000	1000–10 000	10 000–100 000	≥100 000
Largest tumor size, including uterus [cm]	<3	3–5	>5	–
Sites of metastases	Lung	Spleen, kidney	GI	Brain, liver
No. of metastases	0	1–4	5–8	>8
Previously failed chemotherapy	None	None	Single drug	Two or more drugs

FIGO: Fédération Internationale de Gynécologie et d’Obstétrique (International Federation of Gynecology and Obstetrics); GI: Gastrointestinal; hCG: Human chorionic gonadotrophin; NCCN: National Comprehensive Cancer Network.

Prognosis

The prognosis for GTD is generally good. Patients with localized low-risk GTD can be cured and have excellent survival rates. The prognosis for patients with localized high-risk GTD or low-risk metastatic GTD is also favorable. With or without surgery, even high-risk metastatic GTD has healing rates of 80–90% if a combination of chemotherapy and radiotherapy is applied [102, 103].

Low-risk disease

Over 80% of cases of HM are considered benign. The risk of developing invasive disease in CHM is 15–20%, while in partial HM it is 1–5% [1]. Patients who develop GTD have a low risk of persistence in 95% of cases. In most cases, monotherapy with Methotrexate or Dactinomycin is the treatment of choice. If first-line therapy fails, usually due to resistance, it can be easily followed by second-line chemotherapy or occasionally third-line therapy, resulting in an overall survival rate of nearly 100% [6].

High-risk disease

Most patients with high-risk GTN present with metastases months or years after causative pregnancy. Signs and symptoms vary depending on the location of the disease. For example, patients with cerebral metastases may experience headaches, seizures, or hemiparesis. In contrast, patients with pulmonary metastases may present with pleuritic chest pain, shortness of breath, or hemoptysis. Recommended imaging investigations include a CT scan of the whole body, brain MRI, pelvic MRI, and Doppler US. If the brain MRI does not reveal metastatic foci, a lumbar puncture is recommended to assess the ratio of cerebrospinal fluid to serum hCG [6].

Complications

Complications of GTD can be surgical and/or medical in nature. Surgical evacuation of a MP should be performed when the patient is medically stable [104]. For patients with an enlarged uterus who are to undergo surgical evacuation, it is recommended to transfer them to a hospital unit that has intensive care capabilities, the possibility of blood transfusion, and anesthetic support [92].

Commonly reported medical complications associated with HM include hyperemesis, hyperthyroidism, vaginal bleeding, anemia, preeclampsia, and respiratory distress [6]. Pulmonary complications are less common and include pulmonary edema, pulmonary embolism, pleural effusion, and trophoblastic embolization [105]. In patients with high hCG levels or suspected hyperthyroidism, surgery and anesthesia may precipitate a thyroid storm, and beta-adrenergic blockers should be administered [106]. Respiratory distress may occur during and/or after evacuation. Trophoblastic pulmonary embolism, preeclampsia, and thyroid storm with high-output heart failure can also lead to respiratory impairment. Anesthesia and recovery room staff must be aware of these potential complications [107].

Without treatment, choriocarcinoma can lead to death. With the advent of chemotherapy, many patients can achieve remission and cure their disease. The use of chemotherapy is associated with risks such as the development of secondary malignant tumors, nausea, vomiting, hair loss, diarrhea, fever, infections, and the need for blood product transfusions [107].

Postoperative and rehabilitation care

Periodic determination of hCG is mandatory after surgery until an undetectable level is reached. Effective contraception is recommended for patients with a prior MP, and oral contraceptives have proven to be a safe option. Achieving another pregnancy may interfere with the weekly monitoring of serum hCG levels and make it impossible to determine the occurrence of invasive molar disease [34, 108].

Atypical case presentations

Materials and Methods

A series of four cases of HM or GTD were fully analyzed clinically and imaging-wise at the Emergency County Clinical Hospital, Craiova, Romania, which were resolved through complex surgical and/or chemotherapy treatment. The US examination was performed using Voluson P6 and E8 US machines, and extensive imaging investigations such as MRI, CT, or PET–CT were also utilized for the distant evaluation of tumor metastases. Surgical techniques varied from aspirational curettage to excisional biopsy or hysterectomy, depending on the case, its severity, the patient’s age, and the desire to preserve fertility, while oncological treatment was applied to patients with an unfavorable prognostic score. HP examination was conducted at the Pathology Department of the Emergency County Clinical Hospital, Craiova, and was subsequently processed at the Research Center for Microscopic Morphology and Immunology, University of Medicine and Pharmacy of Craiova. Tissues were embedded in paraffin, sectioned using the Microm HM 325 rotary microtome at a thickness of 5 μm. They were stained using the classic Hematoxylin–Eosin (HE) staining method, and for immunohistochemical (IHC) study, they were processed according to a standard protocol. First, the slides underwent antigen retrieval by microwaving in a 0.1 M citrate buffer solution at pH 6 or in an ethylenediaminetetraacetic acid (EDTA) solution at pH 9, according to the manufacturers’ specifications (Table 2). Subsequently, the slides were incubated in a 3% hydrogen peroxide solution for 30 minutes to block endogenous peroxidase that could interfere with signal detection, followed by incubation in 3% skim milk saline solution to block nonspecific antibody binding sites. Primary antibodies were then incubated for 18 hours on the tissue applied to the slides in a refrigerator at 4°C, diluted according to optimization (Table 2; Dako, Glostrup, Denmark, and Abcam, Cambridge, UK). The next day, after thoroughly washing the primary antibody in phosphate-buffered saline (PBS), the slides were incubated with secondary antibodies labeled with Horseradish peroxidase (HRP) specific to the species of primary antibodies (Nichirei Biosciences, Tokyo, Japan). The final stage of the reaction was the effective detection of the signal using 3,3’-Diamino-benzidine (DAB, Nichirei Biosciences), after which the sections were counterstained with Mayer’s Hematoxylin, dehydrated, cleared in xylene, and covered with Canada balsam for imaging and analysis. The graphs presented in the study showing fluctuations in hCG values, were created using Microsoft Excel 2010.

Table 2.

Immunohistochemistry panel used

Antibody	Producer	Clone	Antigenic exposure	Secondary antibody	Dilution	Marking
Anti-CK7	Dako	QBEnd/10	Citrate, pH 6	Monoclonal mouse anti-human CD34 Class II	1:50	Endometrial epithelium
Anti-Ki67	Dako	MIB-1	EDTA, pH 9	Monoclonal mouse anti-human Ki67	1:50	Dividing cells
Anti-p53	Dako	DO-7	Citrate, pH 6	Monoclonal mouse anti-human p53	1:50	Tumoral cells
Anti-p57	Invitrogen	KP10	Citrate, pH 6	p57 Kip2 monoclonal antibody	1:400	Tumoral cells
Anti- α -SMA	Dako	1A4	Citrate, pH 6	Monoclonal mouse anti-human SMA	1:100	α -SMA

CD34: Cluster of differentiation 34; CK7: Cytokeratin 7; EDTA: Ethylenediaminetetraacetic acid; α-SMA: Alpha-smooth muscle actin

Case No. 1

A 14-year-old patient, with a history of an uncomplicated birth two years ago, not previously monitored, with a term newborn weighing 2050 g and a spontaneous abortion one year ago for which she underwent aspirational curettage in another hospital unit, presented at the Emergency Department of the Emergency County Clinical Hospital, Craiova for pelvic pain. She had not been evaluated in the past year and had not undergone periodic serum hCG measurements. The decision was made to admit the patient and carry out specific investigations. The hCG level upon admission was 225 802.00 mUI/mL (normal values: 0–5.3 mUI/mL). Clinical examination revealed an enlarged uterus, and US examination detected the presence of a round-oval intramural formation with pronounced vascularization on the Doppler map, measuring 61/46 mm (Figure 1A, 1B, 1C, 1D).

Figure 1.

Ultrasound aspects of the intramural formation: (A and B) Two-dimensional (2D) image showing a large, heterogeneous intramural tumor formation with an irregular contour; (C and D) Intramural tumor formation with intense vascularization on the Doppler map

Further investigations were conducted, and the HP result of the tissue removed during the curettage performed a year ago revealed the presence of an MP, specifically CHM. Additional investigations were decided upon; thus, the cardiology consultation was normal, the chest X-ray did not reveal metastatic foci, the urology consultation and cystoscopy were within normal limits, and thyroid function was normal. An interdisciplinary committee was convened, consisting of a gynecologist, pediatric oncologist, and pediatric surgeon, and based on clinical, anamnesis, and imaging data, a diagnosis of “invasive GTD” was established as probable. A biopsy was recommended using an aspirational cannula, but the result was inconclusive. The biopsy was repeated, and the result remained inconclusive. Given the intramural location of the tumor formation, it was decided to perform exploratory laparotomy with excisional biopsy. Intraoperatively, uterine tumor ablation, left salpingectomy, omentectomy, adhesion lysis, lavage, and drainage of the peritoneal cavity were performed. The intraoperative HP examination revealed, upon macroscopic examination, a fragment of the uterine body measuring 70/70/50 mm, with the left fallopian tube detached from the attachment to the uterine body. On section, the tumor formation measured 55/50 mm and appeared to invade the myometrium close to the serosa. The tumor tissue exhibited a hemorrhagic brown color with small cystic and necrotic areas. At the level of the uterine horn, there was a formation that appeared to infiltrate and break through the serosa (Figure 2A, 2B, 2C).

Figure 2.

(A and B) Macroscopic aspects of the excisional biopsy specimen; (C) Section through the tumor structure revealing the presence of tumor tissue with a brown, hemorrhagic color, featuring small cystic and necrotic areas

Microscopic examination revealed tumor proliferation with polygonal and spindle-shaped cells, some exhibiting marked atypia, multinucleate cells, and extensive areas of unstructured (tumor) necrosis, invading the myometrium. The intraoperative HP appearance suggested a high-grade malignant tumor – possibly choriocarcinoma. After embedding in paraffin, islands of neoplastic cells of the CTB and SCT type were identified, with marked atypia, increased mitotic activity, including atypical mitoses, invading the myometrium close to the serosa, with extensive areas of necrosis and the presence of neoplastic emboli (Figure 3A, 3B). At the level of the fallopian tube, small groups of cells with an epithelial appearance and minimal atypia were identified. At the level of the omentum, adipose tissue with fibrous septa was detected, showing fibrinohematic microthrombi, hematological infiltrate, and chronic inflammation with frequent siderophages and groups of cells with epithelial morphology, exhibiting minimal atypia. The IHC examination using the anti-CK7 antibody revealed the presence of disseminated tumor cells in the myometrial structure (Figure 3C), while the anti-Ki67 antibody demonstrated a high density of dividing cells, with a proliferation index of over 80% (Figure 3D). It was decided to conserve the uterus, considering the patient’s age and her desire to remain fertile, given the atypical situation regarding the type of GTD and the tumor size.

Figure 3.

Microscopic aspects of choriocarcinoma: (A) Neoplastic cell islands are visible, showing marked atypia, increased mitotic activity, including atypical mitoses, invading the myometrium; (B) Tumor emboli are identified within the blood vessel structure; (C) Tumor cells invading the myometrium are stained brown using immunomarking with the anti-CK7 antibody, ×200; (D) Dividing cells are highlighted at the nuclear level using immunomarking performed with the anti-Ki67 antibody, ×200. HE staining: (A and B) ×200. CK7: Cytokeratin 7; HE: Hematoxylin–Eosin

Regarding the assessment of distant disease extension, no secondary distant lesions were detected through MRI of the brain and abdominopelvic area, as well as CT scans of the chest, abdomen, and pelvis. Based on clinical and paraclinical data, the case was classified as stage II according to the FIGO staging for GTN (left parametrial invasion). Based on the preoperative hCG value (>200 000 mIU/mL), the tumor size (including the uterus) of 80/100 mm, and the interval since the MP of over 12 months, a FIGO prognostic score for GTD of 10 was calculated, placing the patient in the high-risk group and supporting the indication for polychemotherapy. The patient was transferred to the Pediatric Oncology Department, and the Etoposide–Cisplatin (EP) induction regimen was initiated, followed by five cycles of polychemotherapy: Etoposide–Dactinomycin–Methotrexate–Vincristine–Cyclophosphamide (EMA-CO). Under strict clinical, biological, and imaging surveillance according to recommendations, and with treatment using combined oral contraceptives, the hCG values decreased until they became undetectable (Figure 4), and the patient is currently under periodic follow-up. The patient’s hormonal status has remained within normal limits during polychemotherapy, and imaging investigations have not revealed any other changes.

Figure 4.

Gradual decrease of hCG levels during polychemotherapy treatment. hCG: Human chorionic gonadotropin; EMA-CO: Etoposide–Dactinomycin–Methotrexate–Vincristine–Cyclophosphamide

Case No. 2

A 26-year-old patient, with a history of one vaginal delivery in 2021 and three elective abortions, with no reported personal pathological history, presented to the Emergency Department of the Emergency County Clinical Hospital, Craiova for a positive pregnancy test and metrorrhagia. The local examination upon admission revealed vaginal bleeding and an enlarged uterus corresponding to a 15–16 week pregnancy. The hCG level was 664 177 mUI/mL at the time of admission. The US examination showed a uterine cavity with heterogeneous content, predominantly echogenic, without vascularization, containing multiple small anechoic zones resembling vesicles, and two anechoic areas. The overall uterine content measured 175/75 mm. Both ovaries had a normal structure. No free fluid was detected in the retrouterine area (Figure 5A, 5B).

Figure 5.

Imaging aspects of the uterine content: (A and B) Uterine cavity with heterogeneous content, predominantly echogenic, without vascularization, containing multiple small anechoic zones resembling vesicles and two anechoic areas (yellow arrows)

In this case, it was decided to evacuate the uterine cavity through suction curettage, and the extracted tissue fragments were sent to Pathology Department for HP examination. After evacuation, periodic hCG measurements were recommended until the levels fell below 5 mUI/mL, to avoid achieving another pregnancy for a year, to administer combined oral contraceptives, and to return for the HP examination. Shortly after evacuation, the patient returned to the Emergency Department due to pelvic-abdominal pain. It was observed that the hCG levels were increasing after evacuation (Figure 6).

Figure 6.

Oscillations of human chorionic gonadotropin (hCG) levels after evacuation

Upon re-evaluation with US, the uterus appeared with almost normal dimensions, the myometrium was relatively homogeneous, except for an indistinctly defined area at the level of the posterior uterine wall and the left uterine border, which was slightly non-homogeneous and showed minimal vascularization on the Doppler map. The uterine cavity was virtually empty, with a linear endocervix, and both ovaries appeared normal in appearance and size (Figure 7A, 7B).

Figure 7.

Ultrasonic aspects of the uterine structure after evacuation: (A) Two-dimensional (2D) appearance of the non-homogeneous uterine structure at the level of the posterior uterine wall is observed; (B) Minimal vascularization is seen on the Doppler map, outlining the non-homogeneous myometrial structure

Microscopic examination of the aspirated tissue showed the presence of frequent hydropic villi, some with invaginations and circumferential trophoblastic hyperplasia, occasionally with polar distribution of villous trophoblast, decidua with dilated glands lined with atrophic epithelium, and relatively frequent bitrophoblastic mesenchymal villi. This appearance is suggestive of partial HM (Figure 8A, 8B, 8C).

Figure 8.

Microscopic aspects of the analyzed tissue: (A–C) Frequent hydropic villi are observed, some with invaginations and circumferential trophoblastic hyperplasia, occasionally with polar distribution of villous trophoblast, decidua with dilated glands lined with atrophic epithelium, and relatively frequent bitrophoblastic mesenchymal villi. Hematoxylin–Eosin (HE) staining: (A–C) ×200

Given the increase in hCG levels, it was decided to perform additional imaging investigations. Using a chest CT scan, discrete iodophilic tissue nodules were identified, located subpleurally in the middle lobe, lateral segment, measuring 4/4 mm; in the right lower lobe, fewer in number, with maximum dimensions of 7/8 mm; in the medial segment, tangent to a vascular branch; and in the left lower lobe, fewer in number, with maximum dimensions of 10/9 mm; in the anteromedial segment, with a minimal “ground-glass” halo and associated linear fibrosis lesions at this last level, with a potentially suspicious aspect (to be correlated with clinical and paraclinical data from the history) (Figure 9A). The abdominal and pelvic CT did not reveal any changes. Considering all these aspects, IHC analysis of the aspirated tissue was recommended, and a diagnosis of GTN was suspected, which could be an invasive mole or even choriocarcinoma. The IHC analysis confirmed a diagnosis of CHM, in contrast to the initial diagnosis of partial HM. Large, hydropic chorionic villi with central cysts and inconspicuous vascularization were visualized, showing paucicellular mesenchyme and exuberant trophoblastic proliferation, with increased mitotic activity and cytonuclear atypia. Using the anti-p53 antibody, positive nuclear zones were visualized in rare cells, with a “wild type” expression pattern and normal p53 immunostaining (Figure 9B). Additionally, immunostaining with the anti-p57 antibody was negative in the villous CTB, with positive control in the intervillous trophoblast (Figure 9C). With the anti-Ki67 antibody, a high proliferation index of 60% was established in the CTB cells of the villi (Figure 9D).

Figure 9.

Imaging and immunohistochemical aspects of the presented case: (A) The presence of nodular areas within the structure of the pulmonary parenchyma is visualized on the chest computed tomography (CT) scan; (B) Positive nuclear zones in rare cells, with a “wild-type” expression pattern and normal p53 immunostaining, ×200; (C) p57 immunostaining was negative in the villous cytotrophoblast (CTB), with positive control in the intervillous trophoblast, ×100; (D) Cells undergoing division, immunostained with the anti-Ki67 antibody at the level of the villous CTB, ×200

Given the oscillating increase in hCG levels and the aspects of the chest CT that may suggest the presence of pulmonary metastases, the suspicion of GTN increased. A PET–CT was recommended, which did not reveal the presence of metabolically active lesions throughout the body. After this episode, the hCG levels began to gradually decrease, and after a period of two months, the value reached 0.2 mUI/mL. The patient is currently on combined oral contraceptives, and the fluctuations in hCG have classified this case as atypical.

Case No. 3

A 25-year-old female patient, with a history of two miscarriages, one spontaneous in the first trimester and one medical abortion for a pregnancy of five weeks that stopped evolving two months prior to her current presentation at the Emergency Department of the Emergency County Clinical Hospital, Craiova came in for pelvic-abdominal pain. The patient had previously been admitted to another hospital unit with the diagnosis of an unspecified location pregnancy (diagnosis of a pregnancy of an unspecified location), with elevated hCG levels, for which she underwent two courses of Methotrexate, at intervals of seven days, with the recommended doses of 50 mg/m2 body surface area. Four days after the second course of chemotherapy, the hCG level was 438 mUI/mL, after another four days it was 432 mUI/mL, and after an additional six days it rose to 570 mUI/mL, indicating an increase, which led to the decision to perform a uterine biopsy curettage. The HP result showed tissue fragments of endometrium in the proliferative phase. The hCG levels gradually increased to 750 mUI/mL, and the US examination did not reveal any suspicious pelvic ectopic foci, prompting the decision to perform exploratory laparoscopy. Intraoperatively, the following aspects were noted: the uterus, left ovary, and right adnexa appeared normal, while the left fallopian tube showed dilatation of the isthmic portion of approximately 10/15 mm (Figure 10A, 10B, 10C, 10D).

Figure 10.

Intraoperative aspects of the external genital organs: (A) Right fallopian tube with a normal appearance (yellow arrow); (B and C) Left fallopian tube showing dilatation of the isthmic portion; (D) Left periadnexal adhesional syndrome

Given the pathological aspects of the left fallopian tube, it was decided to perform a left salpingotomy, and tissue fragments were extracted that did not suggest trophoblast for HP examination. Intraoperatively, a surgical consultation was requested for exploring the abdominal cavity and excluding an abdominal ectopic pregnancy. The HP examination of the tubal fragments revealed only stasis and chronic inflammatory infiltrate. Subsequently, the decision was made to administer the third dose of Methotrexate, and it was recommended to measure hCG levels on day 4 and day 7 post-administration. The hCG levels decreased minimally and then began to rise again (Figure 11).

Figure 11.

Oscillating human chorionic gonadotropin (hCG) values in this case. A gradual increase in hCG levels is observed, followed by a minimal decrease and then an increase after the third course of Methotrexate

Given these oscillations, additional imaging investigations were decided upon. The cranial CT did not reveal any pathological formations; however, the chest CT detected a nodular formation of approximately 15.7/13.7 mm in the left lower lobe, lateral basal segment, with mixed densities, including fatty components, irregular contours, peripheral iodophilia, and at the level of some internal septa, tangent to the parietal pleura, with minimal thickening (Figure 12A). Considering these aspects, surgical intervention was deemed necessary due to the suspicion of metastatic GTN in the lungs. An atypical resection of the left upper lobe and an excisional biopsy of the left lower lobe were performed, and the excised pulmonary tissue was sent for HP examination. The HP diagnosis was GTN, choriocarcinoma, stage III FIGO due to the presence of pulmonary metastasis, with a prognostic score of 4, favorable, considering the patient’s age, previous miscarriage, the interval of less than four months from the initial pregnancy, hCG levels below 1000 mUI/mL, pulmonary localization, and failure of monochemotherapy. Microscopic examination revealed polygonal and spindle-shaped tumor cells with marked atypia (Figure 12B), some of which were multinucleated, and areas of non-structured tumor necrosis. IHC studies showed the tumor cells to be strongly positive for CK7 (Figure 12C), cells undergoing division were strongly positive for Ki67 immunostaining, and the cellular proliferation index was high, at 85% in the tumor cells (Figure 12D). To analyze the extent of the disease distally, a postoperative PET–CT was decided upon, which did not reveal metabolically active lesions throughout the body. Periodic measurement of hCG levels was recommended, which remained within normal limits postoperatively for one year. The patient avoided achieving another pregnancy during the first postoperative year by using barrier methods. At 18 months postoperatively, the patient achieved a normal pregnancy. Atypical for this case was the pulmonary localization of the choriocarcinoma, without being able to definitively specify that the primary point of origin of the tumor cells was at the genital level.

Figure 12.

Imaging and immunohistochemical aspects of pulmonary choriocarcinoma: (A) CT appearance of the pulmonary nodule detected in the left lower lobe, lateral basal segment (yellow arrow); (B) Polygonal and spindle-shaped tumor cells with marked atypia; (C) Tumor cells strongly positive for immunostaining with anti-CK7 antibody, ×200; (D) Tumor cells undergoing cellular division, immunostained with anti-Ki67 antibody, ×200. HE staining: (B) ×100. CK7: Cytokeratin 7; CT: Computed tomography; HE: Hematoxylin–Eosin

Case No. 4

The 44-year-old patient, known in her obstetric history for three vaginal deliveries and one elective abortion, and in her personal medical history with hypothyroidism under hormonal treatment and chronic smoking, presents to the Emergency Department of the Emergency County Clinical Hospital, Craiova for abundant metrorrhagia that began two days ago. Upon clinical examination, the presence of intravaginal clots and a macroscopic lesion of the cervix was detected, and upon vaginal examination, the uterus was enlarged to the size of a 20-week pregnancy. The pregnancy test was weakly positive, but the hCG level was over 1 000 000 mUI/mL upon admission. Clinical and paraclinical investigations revealed the presence of mild anemia, with a hemoglobin value of 10.3 g/dL. US examination showed an enlarged uterus up to the level of the umbilicus, with the uterine cavity containing a heterogeneous mass, predominantly echogenic, with no vascularization, and multiple small anechoic areas, suggestive of a CMP (Figure 13A, 13B). Both ovaries had a normal structure and size, with no signs of ovarian hyperstimulation (Figure 13C, 13D).

Figure 13.

Ultrasonographic aspects of the genital organs: (A and B) The uterine cavity is observed containing a heterogeneous mass, predominantly echogenic, without vascularization, with multiple small anechoic areas resembling vesicles, which appears to invade the uterine wall – suggestive of an invasive complete mole; (C and D) Both ovaries show normal structures and sizes on two-dimensional (2D) examination

CT examination of the abdomen did not reveal significant changes; however, pulmonary CT examination identified round-oval pulmonary nodules, with diffuse contours, non-iodophilic, predominantly subpleural in disposition, located bilaterally in the lungs. The largest nodules were found in the ventral segment of the right upper lobe, with diameters of up to 6.1 mm, and in the ventral segment of the left upper lobe, with diameters of up to 6.9 mm.

Considering the hCG level, the patient’s age, the abundant metrorrhagia, the macroscopic appearance of the cervical lesion, the presence of pulmonary nodules, and the US findings suggesting CMP with myometrial invasion, it was decided to perform a total hysterectomy with bilateral adnexectomy and wide colpectomy, with the specimen sent to Pathology Department for HP examination. Macroscopic examination revealed a significantly enlarged, globular uterus (Figure 14A) with an elongated hypertrophic cervix. Upon sectioning, transformed ovular remnants were observed, with a ‘bunch of grapes’ appearance, friable, with hemorrhagic areas that dilated the endometrial cavity up to 100 mm (Figure 14B).

Figure 14.

Macroscopic aspects of the total hysterectomy specimen with bilateral salpingectomy: (A) Macroscopic appearance of the enlarged uterus, comparable to a 20-week pregnancy, globular; (B) Macroscopic features on the uterine section highlighting the presence of transformed ovoid remnants, resembling “bunches of grapes”, friable

Microscopic examination of the tissue fragments revealed the following aspects: the cervical tissue was covered by squamous epithelium with parakeratosis and the presence of cervical intraepithelial neoplasia III (CIN III), along with glands showing squamous metaplasia and CIN III (Figure 15A). The myometrium exhibited the presence of large hydropic villi with irregular contours, avascular, and containing cysts, along with circumferential trophoblastic hyperplasia, exhibiting a disordered appearance and confluence along the villous surface, with nuclear atypia and evidence of invasion at the myometrial level, consistent with invasive CHM (Figure 15B). Additionally, there were blood vessels with groups of cells showing intraluminal CTB appearance (Figure 15C, 15D).

Figure 15.

Microscopic aspects of invasive complete mole in the myometrium: (A) The exocervical mucosa is visualized with the lesion area showing CIN III/HSIL; (B) Presence of large hydropic villi with irregular contours, avascular, containing cysts, and circumferential trophoblastic hyperplasia with a disordered appearance; (C) Evidence of trophoblastic invasion at the myometrial level; (D) Presence of cytotrophoblastic cells within the structure of a blood vessel (yellow arrow). HE staining: (A–D) ×200. CIN III: Cervical intraepithelial neoplasia III; HE: Hematoxylin–Eosin; HSIL: High-grade squamous intraepithelial lesion.

IHC examination confirmed the diagnosis of CIN III with dividing cells immunolabeled using the anti-Ki67 antibody throughout the epithelial thickness (Figure 16A). Trophoblastic cells immunolabeled with the anti-CK7 antibody were found among myocytes (Figure 16B). The intervillous trophoblasts were positive for labeling with the anti-p57 antibody and negative in the structure of villous CTB and stromal cells (Figures 16C, 16D). The cell proliferation index was moderate, at 45%, with dividing cells highlighted using immunolabeling with the anti-Ki67 antibody (Figure 16E). Additionally, the presence of myocytes immunolabeled with the anti-α-SMA antibody interspersed with trophoblastic cells confirmed the diagnosis of invasive CHM in the myometrium (Figure 16F).

Figure 16.

Immunohistochemical aspects of invasive CHM in the myometrium: (A) The lesion area showing CIN III, with dividing cells immunolabeled using the anti-Ki67 antibody throughout the epithelial thickness, ×200; (B) Trophoblastic cells immunolabeled with the anti-CK7 antibody were present among myocytes, ×100; (C) Intervillous trophoblasts were positive for labeling with the anti-p57 antibody, ×200; (D) Villous cytotrophoblast and stromal cells were negative for labeling with the anti-p57 antibody, ×100; (E) Dividing cells immunolabeled with the anti-Ki67 antibody were present at a rate of 45%, ×100; (F) The presence of myocytes immunolabeled with the anti-α-SMA antibody interspersed with trophoblastic cells confirmed the diagnosis of invasive CHM in the myometrium. α-SMA: Alpha-smooth muscle actin; CHM: Complete hydatidiform mole; CIN III: Cervical intraepithelial neoplasia III; CK7: Cytokeratin 7

The type of surgical intervention performed was atypical for this case, carried out urgently due to abundant metrorrhagia.

Discussions

GTDs comprise a heterogeneous group of pathologies originating in the trophoblastic epithelium and characterized by a distinct marker (β-subunit of hCG). These disorders have a variable potential for local invasion and metastasis but generally respond extremely well to chemotherapy. Incidence rates of GTD differ worldwide, but the extent to which these differences are attributable to the definitions used and diagnosis is unclear [107, 109]. Our study has shown that the detection rate of these pathologies may vary according to ethnicity, age, and the presence of a previous MP, and that it is extremely important to correctly manage cases and follow up as recommended. In Case No. 1, the young female patient had a HP diagnosis of complete molar, but she did not follow the medical recommendations, did not dose her hCG values in dynamics and did not refrain from getting another pregnancy for at least one year, which is why the benign pathology, complete MH turned into GTN, choriocarcinoma that required extensive surgery. However, considering the patient’s age, a total hysterectomy was not resorted to, leaving her with the possibility of obtaining a pregnancy in the future, after polychemotherapy and negative hCG values during monitoring. In the second case, the presence of histopathologically diagnosed complete MH and oscillating hCG values raised the suspicion of myometrial invasion, considering the ultrasonographic appearance that showed the presence of a heterogeneous formation in the posterior uterine wall. In this situation, the imaging analysis was favorable, and the PET–CT analysis did not reveal any suspicious formations. Sironi et al. performed a retrospective study on three patients to evaluate the role of PET–CT in detecting metastases in GTN. Their results suggested that PET may be useful for the evaluation of metastatic GTN [110].

Chang et al. investigated a series of 14 patients with GTN and found that PET was able to detect chemotherapy-resistant lesions in 43.8% of patients, exclude false-positive CT lesions, detect an additional lesion not found by conventional imaging in a patient with high-risk GTN at the start of primary chemotherapy, and confirm complete response to treatment or salvage therapy for recurrent/resistant GTN. This study suggests that PET–CT may be useful in selected patients with GTN with its ability to provide accurate mapping of metastases and tumor extension, monitor response to treatment, and locate viable tumors after chemotherapy [111]. In the cases reviewed by our team, PET–CT evaluation was required in two of the cases; in two cases pulmonary metastases were excluded, and in the third case, postoperatively, the possibility of other pulmonary metastatic lesions was excluded.

Dhillon et al. studied 11 patients with recurrent GTN and showed a possible role for PET–CT in identifying residual disease in women with recurrence after previous GTN treatment, although other imaging modalities are needed to reduce the risk of false-positive and false-negative results [112]. Cortés-Charry et al. reported two patients with choriocarcinoma in whom PET was useful in detecting metastatic sites that had not previously been identified by conventional imaging [113, 114]. Other studies have suggested that, in patients with GTN, PET–CT can identify hidden metastases, particularly in the lung parenchyma, liver and pulmonary artery [110, 114, 115]. However, although there are guidelines available for the management of patients with GTN, there is no standardization of imaging procedures that can be used in the different phases of the disease, from staging to evaluation of resistance to chemotherapy [96]. In all four cases analyzed, ultrasonographic evaluation helped us to make the diagnosis of trophoblastic disease. Ultrasonography being the main tool for the diagnosis of GTD [34]. The classic appearance described by studies of a MP on ultrasonographic examination with the “snowstorm” or “grape cluster” pattern of the uterus [116] was identified only in the fourth case described and partially in the second case where areas of this description alternated with other heterogeneous areas in the endometrial cavity.

Regarding the starting point of trophoblastic disease, in the analyzed cases, we observed that in Case No. 1, the presence of neglected MP led to its transformation into a choriocarcinoma, similar to studies in literature [117]. In the second case, the suspicion of invasion was given both by the variations of hCG values and by the ultrasonographic aspects, but the correct management of the case led to the negativation of hCG values. In the third case, the pathogenesis is under question. A possible starting point could have been pregnancy arrested and medically evacuated, as no trophoblastic fragments were found in the uterus after chemotherapy with Methotrexate. The regression of the gonadal tumor and the presence of gonadal choriocarcinoma metastases by a trophoblastic embolus related to the gestational event may thus be implicated, but the transformation of a primary non-trophoblastic lung tumor into a choriocarcinoma or the origin from primordial twin cells remaining after abnormal migration during embryonic development cannot be excluded [118].

All the symptoms present both in our cases and in literature studies, such as vaginal bleeding or pelvic-abdominal pain, uterine enlargement and increased hCG value [1, 31, 32], in conjunction with imaging features, could outline the diagnostic likelihood of GTD. From a biological perspective, patients diagnosed with these pathologies may also have elevated liver enzyme levels, which is why non-alcoholic steatohepatitis (NASH) may be suspected. The difficulties encountered in diagnosing and treating this disease are related to a lack of understanding of the pathogenic process, so the ultimate aim of many studies is to establish the factors responsible for the transformation of hepatic steatosis into steatohepatitis and cirrhosis [119].

Patients may have a history of deep vein thrombosis, which is why it is necessary to initiate treatment with new generation oral anticoagulants (NOACs). For anticoagulant medications, the efficacy profile refers to the prophylaxis of thromboembolic events associated with certain clinical conditions, such as atrial fibrillation, postoperative status, neoplasia, thrombophilia, etc., while the safety profile considers, first of all, bleeding, i.e., onset, location, and severity [120]. The clear, conclusive diagnostics were established by HP examination. In Cases Nos. 1 and 4, microscopic examination revealed the presence of solid sheets of atypical SCT, CTB and ITB. No chorionic villi were detected, and sheets or chordae of mononuclear tumor cells are surrounded by layers of multinuclear SCTs. Areas of tumor necrosis and vascular emboli were also detected, similar to the aspects described by other studies in the literature [71, 72, 73, 74]. In our study, based on data from the literature [75], we used CK7 and detected the presence of tumor cells both in the myometrium in Case No. 1 and at the pulmonary level in Case No. 3. In both cases, the tumor proliferation index was high, and the percentage of tumor cells exceeded 80%, similar to studies reported in the literature [75]. Tumor cells were highlighted with CK7, while smooth muscle cells were immunolabeled with the anti-α-SMA antibody [121]. In Cases Nos. 2 and 4, the presence of diffuse thickening of the villi with marked hydropic changes, formation of cysts, and marked trophoblastic hyperplasia with cytological atypia was identified, similar to previously published studies [15, 16, 65]. IHC aspects aided in the differential diagnosis with partial HM, both through the characteristics of the villi and the negative reaction to p57 at the level of villous CTB and stromal cells. In tumorigenesis, abnormal functions of p57 contribute to the initiation and progression of cancer. p57 was initially reported to have a role in inhibiting proliferation and is considered a tumor suppressor gene. It has now been discovered that p57 is also involved in regulating other cellular processes, including apoptosis, differentiation, development, and migration in tumorigenesis. Clinical studies also show that p57 is a marker of aggressive phenotype and tumor prognosis [122]. In the case of patients with a good prognostic score, the post-evacuation evolution is often favorable. However, in cases with poor prognosis, with a score above 7, such as in Cases Nos. 1 and 4, careful management is required after evacuation, as the risk of recurrence is significant. First, diagnosing the disease and its complications is difficult; this presents significant challenges for subsequent treatments, given that approximately 80% of GTN cases have distant metastatic lesions with different clinical manifestations. Many studies report that women with liver, splenic, or pelvic lesions may present with abdominal pain and massive hemoperitoneum. Nervous system involvement can manifest as hemiparesis, paresthesia, or seizures. Acute intracranial hemorrhage can lead to loss of consciousness and sudden collapse. Metastases in the digestive tract, including gastric, colonic, rectal, and small bowel metastases, may present as upper gastrointestinal bleeding, melena, perforation, and intestinal obstruction [123, 124, 125, 126, 127, 128, 129]. In our Center, similar to other tertiary centers that operate according to national and international guidelines, early recognition and management of GTD with high professionalism by the MDT have led to the successful resolution of the described cases. Gynecologists lead the MDT, and with the help of oncologists, surgeons, and radiotherapists, a treatment plan is established based on each patient, as well as the prevention and management of postoperative complications [130, 131]. In our Center, surgical intervention for GTN, especially in emergencies and critical conditions, is performed to save patients’ lives and restore stable vital functions. This is not carried out for the purpose of radical intervention; instead, we select conservative surgical interventions, such as local resection of the lesion, as in Case No. 1, rather than total organ resection, as in hysterectomies, to preserve organ functions and reproductive capacity, and to ensure rapid recovery, allowing us to administer postoperative chemotherapy.

Conclusions

The MDT can thoroughly and accurately assess a case of GTD through clinical, paraclinical, and imaging evaluations, allowing them to choose the most appropriate therapeutic approach with minimal adverse effects on patients. Periodic monitoring of patients diagnosed with GTD significantly reduces the risk of malignant transformation and progression of this pathology, which can thus be cured. Clinical and imaging characteristics suggestive of GTD can only be confirmed through HP examination, which remains the sole method for accurate diagnosis and classification of GTD. This HP confirmation is crucial for determining the appropriate treatment strategy and ensuring effective management of the disease, as it provides definitive insight into the nature of the trophoblastic lesions.

Conflict of interests

The authors declare that they have no conflict of interests.