Mesenteric desmoid tumor after laparoscopic resection of stage I endometrial cancer: A case report

Abstract

Mesenteric desmoid tumors (DTs) are rare, and there are no specific imaging features that can aid definitive diagnosis. This article presents the case of a 61-year-old woman found to have intra-abdominal DT located in the mesentery at two-year follow-up after laparoscopy-assisted anterior resection for stage I endometrial cancer. Computed tomography (CT) indicated the presence of a solitary tumor arising from the intestinal wall or mesentery. Subsequent magnetic resonance imaging and integrated positron emission tomography/CT with 2-¹⁸F-fluoro-2-deoxy-d-glucose suggested DT rather than recurrence, but surgical resection was chosen after considering the potential risks. Surgery confirmed the diagnosis, revealing a tumor at the level of the jejunal mesentery and approximately 5 cm in diameter. The mesenteric tumor was resected, along with part of the jejunum and the greater omentum. Histopathological examination of the surgical specimens confirmed the diagnosis of DT. As mesenteric DT after laparoscopic resection of stage I endometrial cancer is rare, a high degree of suspicion is necessary for diagnosis. Given that laparoscopic surgery is increasingly used in gynecological clinical practice, gynecologists and radiologists should be aware that DT should be considered in the differential diagnosis when a mesenteric mass is detected during follow-up after a surgical procedure, including laparoscopy.

Highlights

• •Mesenteric desmoid tumor may appear as a solid mass on radiological imaging.
• •Desmoid tumor demonstrates delayed or mild enhancement on dynamic contrast-enhanced MRI.
• •Dynamic contrast-enhanced MRI, diffusion-weighted imaging, and FDG-PET are useful for the diagnosis of desmoid tumor.

1. Introduction

Desmoid tumors (DTs) are rare entities associated with familial adenomatous polyposis, surgical trauma, and hormonal factors. They often occur in the abdominal wall or extremities but rarely in the abdominal cavity. Intraperitoneal DTs have been reported after conventional open surgery or laparoscopic surgery [1], but most of these cases have occurred after surgery for tumors of the digestive system, such as colorectal cancer; to our knowledge, there have been no such cases after laparoscopic surgery for gynecological tumors. Differentiating between DT and cancer recurrence is often difficult when abdominal DT occurs after cancer surgery [2,3]. This differentiation is important for patients with endometrial cancer because it helps determine the treatment plan. Therefore, we present the radiological findings, particularly those of magnetic resonance imaging (MRI) and integrated positron emission tomography/computed tomography (PET/CT) with 2-¹⁸F-fluoro-2-deoxy-d-glucose (FDG), in the case of mesenteric DT after laparoscopic resection of stage I endometrial cancer.

2. Case Presentation

A 61-year-old postmenopausal woman underwent a total laparoscopic hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection for endometrial cancer. The histopathological diagnosis was endometrial cancer grade 1, pT1aN0M0, stage IA. She was determined to have a low risk of recurrence and did not receive adjuvant therapy. The patient remained disease-free during the 2-year follow-up period.

Routine follow-up abdominal contrast-enhanced CT two years after surgery revealed a well-defined tumor measuring 5 cm located in the mesentery of the small intestine that showed slight heterogeneous enhancement. Peritoneal recurrence was suspected (Fig. 1). The patient then underwent FDG-PET/CT examination for qualitative diagnosis of the current lesion and search for recurrence at other sites, which showed a soft-tissue mass measuring approximately 5 cm located in the middle abdomen (Fig. 2). This mass demonstrated only mild FDG tracer uptake, with a maximum standardized uptake value (SUVmax) of 2.9. The degree of FDG uptake within the mass was less than that expected for malignant processes such as metastasis or lymphoma.

Fig. 1.

Contrast-enhanced CT showed a well-defined mass measuring 5 cm in contact with the small intestine with slightly heterogeneous enhancement (arrows). CT, computed tomography.

Fig. 2.

A solid mass lesion (arrows) near the jejunum showed only mild FDG uptake (SUVmax 2.9). (A) Coronal image of FDG-PET/CT. (B) Axial image of FDG-PET/CT. FDG, 2-[18F] fluoro-2-deoxy-d-glucose; PET/CT, positron emission tomography/computed tomography; SUVmax, maximum standardized uptake value.

An MRI scan of the lower abdomen was performed using a 3-T Magnetom Skyra (Siemens Healthcare, Erlangen, Germany) for a detailed qualitative diagnosis of the lesion. The scan revealed a well-defined isolated mass (approximately 5 cm in diameter) on the side of the proximal jejunum. The mass was isointense with the myometrium on T1-weighted images and showed slightly high homogeneous intensity with peripheral high intensity on T2-weighted images (Fig. 3A, B). No areas suggestive of intratumoral hemorrhage or necrosis were observed. On gadopentetate dimeglumine dynamic contrast-enhanced images, including fat-suppressed T1-weighted images, the periphery of the mass was relatively well enhanced, but the other areas showed gradual and weak enhancement (Fig. 3C, D). On diffusion-weighted imaging (DWI) (b = 800 s/mm²), the major components of the mass, except for the marginal area, showed slight hyperintensity, which was atypical for malignancy (Fig. 3E). Therefore, a non-malignant lesion with a highly fibrous component, including a mesenteric DT, was suspected.

Fig. 3.

The mass (arrows) was isointense with the myometrium on T1-weighted images (A) and showed a slightly high homogeneous intensity with peripheral high intensity on T2-weighted images (B). On Gd-DTPA dynamic contrast-enhanced images, including fat-suppressed T1-weighted images and dynamic study, the periphery of the mass was relatively well enhanced, but the other areas showed gradual and weak enhancement (C, D). On DWI (b = 800 s/mm2), the major component of the mass, except for the marginal area, shows slight hyperintensity (E). Gd DTPA, gadopentetate dimeglumine.

In this case, however, recurrence could not be completely ruled out, and even if it was a DT, there were concerns about life-threatening complications; therefore, an exploratory laparotomy was performed. The intraoperative finding was a 5 cm lesion in the jejunal mesentery, approximately 15 cm from the Treitz ligament. Intraoperative rapid histological examination revealed no malignant findings in the lymph nodes near the mesentery. The mesenteric tumor was resected, along with part of the jejunum and the greater omentum.

Analysis of the resected specimens indicated a grayish white tumor, measuring 54 × 41 mm, in the mesentery that was non-contiguous with the jejunum. Microscopic analysis revealed spindle-shaped tumor cells growing in bundles (Fig. 4). Immunohistochemical studies indicated negative staining for β-catenin (+, nuclear), αSMA (−), CD34 (−), and c-kit (−). Moreover, 1 % of cells were positive for Ki-67 expression. A CTNNB1 variant was identified through a gene-variant search. The final histopathological diagnosis was DT.

Fig. 4.

At high magnification, the lesion was found to be composed of spindle tumor cells without nuclear atypia (100×, H&E).

The patient has been disease-free for 5 years since the surgery. Follow-up examinations, which included enhanced CT and transvaginal sonography, showed no evidence of DT recurrence or endometrial cancer.

3. Discussion

DT, a neoplastic disease, is also known as desmoid-type fibromatosis. Although DTs are highly locally invasive, they do not cause distant metastasis; therefore, they are classified as soft-tissue tumors in the “intermediate group” between benign and malignant tumors in the World Health Organization classification [4]. Association with APC variants can result in multifocal DTs, occasionally leading to mortality.

DTs may progress slowly and regress naturally; however, they may also grow rapidly [5], making them difficult to distinguish from metastases. It is particularly difficult to differentiate when DT occurs at the surgical site of a malignant tumor, as in this case. Intraperitoneal DTs are often observed in patients with familial adenomatous polyposis or Gardner syndrome; however, they can also develop because of trauma or surgery. DTs in wounds after laparoscopic surgery are considered much rarer than those that develop after open surgery. Although there have been reports of recurrence at the port placement site in laparoscopic surgery [6], there have been no reports of intraperitoneal DTs after laparoscopic endometrial cancer treatment.

In the case reported here, intraperitoneal recurrence was suspected on follow-up CT, and further investigation was performed using dynamic contrast-enhanced MRI and FDG-PET because recurrence is rare 2 years after radical resection of stage 1 endometrial cancer [7,8].

Azizi et al. reported that the variable MRI signal characteristics of DTs reflect differences in their composition, especially their cellularity and fibrous content, and that most DTs are heterogeneous soft-tissue lesions with intermediate signal intensity. The lesions show hypointensity or isointensity with respect to the muscle on the T1-weighted images. They are usually mixed but predominantly hyperintense (more than muscle, but usually less than fat) on T2-weighted images. After intravenous injection of contrast material, DTs may show homogeneous, inhomogeneous, or no significant enhancement [9]. The current tumor showed similar findings, and DWI showed an absence of restriction, suggesting a nonmalignant lesion with a high fibrous component, such as a mesenteric DT. Kim et al. summarized the features suggestive of DT as follows: (1) a single lesion at a previous operation site; (2) unresponsiveness to imatinib treatment; (3) a well-defined ovoid lesion with delayed or mild enhancement without necrosis, hemorrhage, or cystic change on CT; (4) mild or no hypermetabolic activity on FDG-PET [10]. In this case, delayed or mild enhancement was also observed on dynamic contrast-enhanced MRI, and the SUVmax on FDG-PET was 2.9, which is consistent with the third and fourth features above. When the primary tumor is at a low stage, as in this case, even if an abdominal tumor appears on a follow-up CT scan, the addition of dynamic contrast-enhanced MRI and FDG-PET may make it possible to suspect DT rather than recurrence.

Some DTs disappear naturally; hence, if the patient is asymptomatic, careful follow-up may be an option [11]. Surgical resection of the lesion was performed in the present case. However, the invasive nature of mesenteric DTs can lead to bowel loops, ureteral obstruction, or vascular injury, resulting in life-threatening complications. If the tumor is resectable, complete surgical resection with a wide surgical margin (at least 1 cm) is the first-line treatment [5]. However, even if completely removed, intra-abdominal DTs have a high rate of local recurrence [11]; therefore, if there is a future recurrence, distinguishing between a recurrence of the malignant tumor and that of DT is necessary. A complete resection of the jejunum was performed, and negative margins were confirmed in the present case; hence, no further treatment was added. Systemic therapies include hormone therapy, nonsteroidal anti-inflammatory drugs (NSAIDs), hormone therapy, chemotherapy, and molecular targeted drugs. In hormone therapy, the antiestrogen drug tamoxifen binds to the estrogen receptor and inhibits cell proliferation. NSAIDs inhibit tumor proliferation by inhibiting the immunosuppressive effects of prostaglandins. However, these treatments are not currently recommended. Contrastingly, chemotherapy and targeted agents such as tyrosine kinase inhibitors are indicated for patients with rapidly growing, symptomatic, unresectable tumors or advanced disease. Radiation therapy is also an option but is used as an adjuvant treatment or for extraperitoneal tumors because of the risk of radiation-induced damage to intraperitoneal structures, including radiation-induced enteritis [5].

In summary, we present a case of mesenteric DT after laparoscopic resection of stage I endometrial cancer. This rare entity may appear as a solid mass on CT and MRI and cannot be adequately distinguished from recurrent tumors. However, dynamic contrast-enhanced MRI, DWI, and FDG-PET may be useful when considering the possibility of DT. Nevertheless, further studies on the correlation between mesenteric DT identification using these modalities are warranted.