Deep infiltrating endometriosis: retroperitoneal endometriosis-a case report

Abstract

Background

Deep infiltrating endometriosis is a subtype of endometriosis. A case of retroperitoneal endometriosis surrounding the ureter and forming a pelvic mass is relatively rare.

Case presentation

A 26-year-old woman was admitted to our department because of unbearable dysmenorrhea and dizziness. CT scan revealed a pelvic mass on the right side of the pelvic cavity. The pain did not alleviate even she received symptomatic treatments. She finally underwent a emergency laparoscopic exploration and a pelvic mass surrounding the right ureter was found during the surgery. We removed the mass successfully with the help of a urologist by inserting a right ureteral stent at last. A retroperitoneal endometriosis was diagnosed by postoperative pathology and GnRh was administered afterwards to prevent reoccurrence.

Conclusion

We herein present a rare case of DIE—a retroperitoneal endometriosis and describe the process of the laparoscopic management. For retroperitoneal masses closely adherent to the pelvic wall, clarifying the course of the ureter is of great importance, and collaboration with urologic surgeons may be necessary when needed. Because there is no-specific imaging features, the benign or malignant nature of the mass might be suspected before surgery.

Background

Endometriosis (EM) refers to the presence of endometrial tissue (including glands and stroma) outside the uterine cavity. It is characterized by clinical manifestations such as pain, infertility, and pelvic masses. Although it is a benign condition, it exhibits malignant biological behaviors such as invasiveness, metastasis, and recurrence [1]. Based on clinical and pathological characteristics, endometriosis can be classified into four subtypes: peritoneal (superficial), ovarian, deep infiltrating, and endometriosis in other locations (such as abdominal wall scars and the lungs), with ovarian being the most common type [2]. For deep infiltrating endometriosis, it can implant in various locations within the pelvic cavity. The most common locations of DIE are uterosacral ligaments (USL), rectovaginal space (RVS), the rectosigmoid, and the bladder [3], Retroperitoneal endometriosis that encases the ureter and grows invasively is relatively rare.

Case presentation

On 27th Jan 2025, a 26-year-old woman came to the emergency department of our hospital, complaining of unbearable dysmenorrhea and dizziness. She had no fever, nausea, vomiting, or diarrhea. Upon detailed inquiry into her medical history, it was found that the patient had irregular menstrual cycles, heavy menstrual bleeding, and severe dysmenorrhea, but she had not received any regular treatment. She denied any history of sexual activity, chronic diseases, and reported no tobacco or alcohol consumption.

After admission, an urgent CT scan was performed, which showed no abnormalities in the uterine morphology, but a heterogeneous density mass with a dimension of approximately 6.7 × 7.0 × 6.9 cm was seen in the pelvic cavity, closely attached to the right ureter (Fig. 1a), and there was a fluid shadow in the pouch of Douglas (Fig. 1b). Iodine injection was not allowed because the patient was taking metformin, which is contraindicated for contrast CT, due to obesity and insulin-resistance. Blood routine examination revealed a hemoglobin level of 56 g/L, the white blood cell count and neutrophil count was within the normal range, both CA125 and CA199 levels showed no abnormality. On examination, no abnormalities were observed in the patient’s vulva. Rectal examination: the uterus is anteverted and of normal size, without tenderness. No mass was palpated in the left adnexal region, but tenderness was present. The right adnexal region is normal without any palpable abnormalities and with no tenderness exiting. No tender nodules are palpated within the pelvic cavity. After admission, the patient was given anti-inflammatory, analgesic, and anti-anemia symptomatic treatments. However, her pain did not alleviate, so she underwent an emergency exploratory laparoscopy at last. During the surgery, the uterus was found to be of normal size and shape, both ovaries and fallopian tubes appeared normal. A purple-blue nodule measuring about 2 × 2 × 2.5 cm was detected on the surface of the left round ligament near the cornua uteri (Fig. 2a). After displacing the right colon, a mass measured 6 × 6 × 7 cm was found on the retroperitoneum, closely attached to the right pelvic wall, with the peritoneum wrapped around it (Fig. 2b). A purple-blue perforation with active bleeding was observed on the mass (Fig. 2c). The mass was carefully and gradually resected during the operation. The mass ruptured during resection, and chocolate-like viscous tissue was found inside the cyst cavity (Fig. 2d). Because the mass was densely adherent to the pelvic wall, to prevent ureteral injury, a urologist was invited to place a right ureteral stent during the surgery (Fig. 2e). The cyst wall tissue surrounding the right ureter was resected, and we irrigated the pelvic cavity copiously with normal saline. Total blood loss was < 80 cc and the surgical process went smoothly.

Fig. 1.

a CT scan showing that the right ureter(yellow arrow pointing to the blue rectangle) is closely adjacent to the cyst measured approximately 6.7×7.0×6.9cm (△ indicate the mass). b CT scan showing the fluid in the pouch of Douglas (yellow arrow pointing to the blue oval)

Fig. 2.

a Intraoperative finding showing that a purple-blue nodule measured 2×2×2.5 cm was detected on the surface of the left round ligament (white arrow). b Intraoperative finding showing that a pelvic mass measured 6×6×7 cm was found on the retroperitoneum closely attached to the right pelvic wall(white arrow) and △ indicate the right ovary. c During the surgery we found a bleeding hole on the surface of the mass. d The cyst ruptured during the surgery and chocolate-like tissue was found inside the cyst cavity (white arrow). e After inserting a ureteral stent during the surgery, we clearly saw the right ureter (white rectangular box ) which was surrounded by the cyst wall (white arrow)

The patient recovered well after the surgery. The postoperative pathology report indicated: (right retroperitoneal lesion) endometriotic cyst; (left round ligament lesion) endometriosis (Fig. 3a and b). The diagnosis was considered to be deep infiltrating endometriosis and round ligament endometriosis. After the surgery, the patient was given GnRh to prevent recurrence. Two months after the surgery, the patient had a follow-up ultrasound examination in the outpatient clinic, which showed no abnormalities.

Fig. 3.

a and b Microscopic findings using hematoxylin and eosin (HE) staining (100×) , We identified the endometrial gland tissues on both images

Discussion and conclusion

In recent years, with the delay in childbearing age and the decline in fertility rates among women, the prevalence of endometriosis has been increasing year by year. Endometrioma, which is the most common type of endometriosis, can cause damage to ovarian function and is more severe when an endometrioma > 4 cm is excised [4]. Also a Meta-Analysis indicated that endometriosis patients have higher rates of comorbidities, including ovarian and endometrial cancer [5]. Additionally, endometriosis has a significant association with higher infertility rates due to chronic pelvic inflammation [6]. According to incomplete statistics, endometriosis affects more than 10% of women of reproductive age, with an infertility rate as high as 30–40% [7]. So timely diagnosis is of great importance to reduce severe complications and improves outcomes. In our case, if the right ureter were compressed for a prolonged period, it could lead to damage such as kidney failure (from ureteric obstruction).

According to the staging system of the American Society for Reproductive Medicine (ASRM), endometriosis can be divided into four stages. But rASRM system can not describe DIE appropriately. Thus the Enzian classification overcomes these issues and has been created to describe DIE using 3 planes or so-called pelvic compartments, representing a more tangible clinical perception of DIE [8].

Endometriosis is a disease with an insidious onset. This is especially true for deep infiltrating endometriosis. Symptoms of individuals with endometriosis range from an absence of symptoms to severe conditions, with chronic pelvic pain and debilitating dysmenorrhea being the most prevalent ones [6]. In this case, even though the patient had dysmenorrhea, retroperitoneal endometriosis was difficult to detect in a timely manner through routine ultrasound of the uterus and adnexa. It remains difficult to assess, with a mean time to diagnosis up to 10 years after the first symptoms, therefore resulting in altering the peritoneal environment or distorting the pelvic anatomy gradually which are unfavorable for conception [9]. It was only when the patient developed an acute abdomen due to rupture of the mass that she was forced to seek medical attention. For women of reproductive age presenting with endometriosis-associated symptoms, gynecologic examination ought to be performed and endometriosis-related pain should be aware of. Noninvasive procedures such as transvaginal sonography (TVS), and magnetic resonance imaging (MRI) have been established for the pre-operative diagnosis of endometriosis, with TVS being suggested as the first line approach to be used in the assessment of women with suspected endometriosis The use of such instrumentation offers a relatively easy way to apply approach aiding in clinical diagnosis, empowering clinicians to start first-line treatment early on the basis of a clinical diagnosis and decrease the likelihood of long-term sequelae of the disease [7]. Moreover, surgical treatments have developed fast over recent years; thus, DIE can now be diagnosed and treated in a minimally invasive manner in most cases [10–12]. In this report, since the patient denied sexual experience, TVS was not allowed to perform. Emergency CT scan was prioritized as the initial imaging modality. If a pelvic mass accompanied by pelvic effusion is detected, the patient did not feel better after symptomatic therapy, a high suspicion of mass rupture should be raised. Prompt intervention should be taken into consideration based on the acute abdominal signs. During surgery, it is important to carefully dissect the adhesions around the mass. It is necessary to involve a urologist to place a ureteral stent before continuing to resect the tissue around the ureter to prevent injury. In a study of 45 patients with ureteral endometriosis, preoperative ureteral stenting in case of impairing urinary function is essential to reduce the ureteral injury rate during surgery [13]. As for such rare clinical conditions, a multidisciplinary team approach involving urologists is recommended for surgical management to improve diagnostic accuracy and reduce risks of such surgery because of its complexity [14]. Given the propensity of endometriosis to recur, postoperative drug therapy is administered to control the condition, long-term management and follow-up are required as well. Besides, concomitant endometriosis is present in approximately 50% of adenomyosis because they are supposed to share the similar underlying mechanisms, involving the presence of endometrial tissue (glands and stroma) in unexpected locations. In that case, the patient’s pain may not be relieved post-operatively. Taking continuous oral contraceptives (COCs) is recommended to alleviate pain and prevent recurrence. Additionally, GnRH agonists represent an alternative treatment choice [15, 16].

The pathogenesis of endometriosis remains unclear, with distinct mechanisms proposed for different subtypes. Classic theories include: a) retrograde menstruation(Sampson’s theory); b)coelomic metaplasia; c)altered immunity and d)theory of endometrial progenitor cells [2, 9]. Currently, it is believed that the pathogenic characteristics of DIE exhibit specificity compared to other types of endometriosis. Studies suggest that, in addition to hormonal function and immunologic factors, its invasive behavior may be mediated through decreased cell apoptosis, increased proliferation activity associated with oxidative stress, and the overexpression of matrix metalloproteinases(MMPs) as well as neuroangiogenesis-related genes [17]. We can hypothesize that the patient initially had superficial peritoneal endometriosis lesions. The lesion gradually enlarged with every menstruation and infiltrated into the retroperitoneum in an invasive growth pattern, eventually forming an endometriotic mass encasing the right ureter.

The malignant transformation rate of endometriosis is about 1.0%, with endometrioid carcinoma and clear cell carcinoma being the most common type [18]. Nevertheless, documented cases of malignant transformation arising from DIE remain exceptionally rare in the literature [19]. In our case, the patient underwent diagnostic laparoscopy due to acute abdomen. Although tumor markers showed no abnormalities, preoperative evaluation remains critical for pelvic mass of undetermined nature. During surgery, further rupture of the mass should be avoided to strictly adherence to the “tumor-free” principle. If necessary, conversion to open surgery should be considered to ensure complete lesion resection, thereby preventing pelvic dissemination and implantation of potentially malignant tissue-factors that could significantly compromise the patient’s prognosis and subsequent treatment.

Abbreviations

CT

Computerized tomography

DIE

Deep infiltrating endometriosis

CA125 and CA199

Cancer antigen125 and cancer antigen 199

GnRh

Gonadotropin-releasing hormone

TVS

Transvaginal sonography

MRI

Magnetic resonance imaging

Authors’ contributions

Hong Xu wrote the manuscript. Ruyue Ma and Ruiheng Zhao revised the manuscript. Huiying Qian, Ruiheng Zhao and Jian Chen participate in the surgery, Yu Zheng collected and interpreted the images. All authors read and approved the final manuscript.

Funding

2024 Academy-level Research Initiation Fund Approval Contract of Suzhou Ninth People’s Hospital (Grant No.YK202415).

Science and Education Project Fund of Suzhou Wujiang District Health Committee (Grant No. WWK202201).

Suzhou Applied Basic Research Science and Technology Innovation Program (Grant No. SYWD2024201).

Science and Technology Development Fund of the Affiliated Hospital of Xuzhou Medical University (Grant No. XYFY202423).

Hospital-level project of the Ninth People’s Hospital of Suzhou (Grant No. YK202202).

Data availability

Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.

Declarations

Ethics approval and consent to participate

The Clinical Medical Research Ethics Committee of the Suzhou Ninth People’s Hospital(NO.KYLW2025-019-01).

Consent for publication

The patient signed informed consent for the publication of this case report and any associated images. A copy of the consent form is available for review by the Editor of this journal.

Competing interests

The authors declare no competing interests.