A case of polypoid endometriosis mimicking advanced ovarian carcinoma with rapid growth, invasion, and dissemination

Abstract

Polypoid endometriosis is a rare form of endometriosis characterized by polypoid masses that histologically often resemble endometrial polyps. We report a case of rapidly progressing polypoid endometriosis that was preoperatively assumed to be advanced ovarian cancer. A 46-year-old woman, para 0, underwent laparoscopic myomectomy and left adnexectomy for uterine fibroids and a left ovarian endometrial cyst after administration of gonadotropin releasing hormone (GnRH) agonist for 4 months. Eleven months postoperatively, rapid right ovarian enlargement occurred. CT and MRI (both contrast-enhanced) showed masses in the right adnexa, cecum, sigmoid colon, and omentum, and PET-CT demonstrated increased uptake, suggesting ovarian cancer and peritoneal dissemination. The patient later developed intestinal obstruction, and colonoscopy revealed multiple polypoid lesions in the sigmoid colon. The omental tumor and right adnexa were biopsied during exploratory laparotomy, and diagnosed as polypoid endometriosis with no malignancy by permanent pathology. The right adnexal tumor shrunk markedly after 4 months of GnRH antagonist treatment. Second laparotomy was then performed for right adnexal tumor resection and ileocecectomy. Pathological examination revealed polypoid endometriosis extending from the ovary to the cecal mucosa. The patient has been asymptomatic for over 1 year postoperatively. The sigmoid colon tumor shrunk but is still present.Polypoid endometriosis predominantly affects the ovaries, colon, peritoneum, and omentum of patients in their 40s and 50s. It is a benign disease but is often difficult to distinguish from malignancy preoperatively because it rapidly forms numerous solid lesions. Although polypoid endometriosis is rare, with no specific imaging findings, including it in a differential diagnosis may facilitate preoperative identification.

Keywords: PET-CT; differentiated diagnosis; endometriosis-associated malignancy; magnetic resonance imaging (MRI); polypoid endometriosis.

Fig. 1.

Findings during first laparoscopic surgery. Laparoscopic subserosal myomectomy (A) and left adnexectomy (endometrial cyst) (B) were performed. Surgical findings showed adhesions in the rectum, sigmoid colon, and posterior wall of the uterus in the pouch of Douglas, and firm adhesions in the right adnexa and ileocecal area (C). When the adhesions were detached, the right ovary was found to be almost normal (D).

Fig. 2.

Findings of CE-MRI of the right ovarian tumor performed about 1 year after the first laparoscopic surgery. CE-MRI showed a lump in the right adnexa and ileocecal area, with a size of about 6 cm × 10 cm. Axial T2-weighted image showing a hyperintense mass (A). Axial T1-weighted image showing isointensity with some hyperintense masses (B). Axial T1-weighted image with gadolinium contrast showing mild tumor enhancement (C). Sagittal T2-weighted image (D). Coronal T2-weighted image (E). Diffusion-weighted image showing slightly high signal intensity (arrow) (F).

Fig. 3.

Findings of PET-CT of the omental tumor. PET-CT showed faint FDG accumulation in the omental tumor in the right upper abdominal wall (arrow) (A, B).

Fig. 4.

Findings of colonoscopy performed before the second surgery and pathologic examination of a biopsy specimen. Colonoscopy showed marked stenosis of the intestinal tract due to multiple submucosal polypoid lesions in the sigmoid colon (A, B, C), and a stent was inserted in the area (D). Pathological examination of a biopsy specimen was suggestive of intestinal endometriosis, because the endometrial grand-like atypical gland were ER-positive (E, F).

Fig. 5.

Histopathological findings of removed organs from the second and third surgeries. Upper row (A, B, C): In the second surgery, removal of the omental tumor was performed and a permanent specimen was pathologically diagnosed as polypoid endometriosis with no malignancy. Lower row (D, E, F): In the third surgery, right adnexectomy and ileocecectomy were performed and pathologically diagnosed as polypoid endometriosis with no malignancy.

Fig. 6.

Findings of transvaginal ultrasonography before and after administration of a GnRH antagonist. The size of the right adnexal tumor markedly decreased after the patient was started on a GnRH antagonist (relugolix; 2 mg/day) following the second surgery. The right adnexal tumor measured 57 mm × 48 mm pre-administration (A), 52 mm × 49 mm 1 month later (B), and 32 mm × 36 mm 3 months later (C).

Fig. 7.

Findings of colonoscopy performed 6 months after the third surgery. Colonoscopy showed that the polypoid tumor of the sigmoid colon was still present but had decreased in size, and that intestinal stenosis had markedly improved (A, B). No abnormalities were observed in the ileocecal region (C).