10.51847/6hd0rsbqk9g828

Endometriosis usually affects premenopausal females. Its pathogenesis is not completely understood. The presence of functioning endometrial glands and stroma outside the uterine cavity is known as endometriosis. Endometriosis can be found in both ovaries, the pouch of Douglas, pelvic peritoneum, and uterosacral ligaments. Cystic forms of endometriosis can occasionally present as a huge abdominal mass, mimicking ovarian malignancy. Hereby, we present one such case of a large endometriotic cyst in a pre‑menopausal female. She underwent surgery, and the histopathology, along with immunohistochemical examination, proved it to be a case of endometriotic cyst. Although this diagnosis is relatively rare, this should be considered as a differential diagnosis in the case of cystic lesions in premenopausal females.

Endometriosis, endometriotic cyst, immunohistochemistry Large Endometriotic Cyst -Masquerading as Ovarian Malignancy Case Report Rashmi Patnayak, Ajit Surya Mohapatra, Nibedita Sahoo, Adya Kinkara Panda, Pendyala Sujata 1, Amitabh Jena2, Debahuti Mahapatra Departments of Pathology, 1Obstetrics and Gynaecology and 2Surgical Oncology, Institute of Medical Sciences and SUM Hospital, Bhubaneswar, Odisha, India How to cite this article: Patnayak R, Mohapatra AS, Sahoo N, Panda AK, Sujata P, Jena A, et al. Large endometriotic cyst‑masquerading as ovarian malignancy. Clin Cancer Investig J 2020;9:22‑4. This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution‑NonCommercial‑ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non‑commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms. For reprints contact: [email protected]

Endometriosis is a common and benign condition. It affects approximately 10% of premenopausal women. [1] The pathogenesis of endometriosis is complicated and has not yet been fully explained. [2] The various sites of endometriosis include both ovaries, the pouch of Douglas, pelvic peritoneum, and uterosacral ligaments. This phenomenon complies with the theory of menstruation back‑flow and implantation of endometrial tissue. [3] Endometriotic cysts are cystic form of endometriosis. These cysts may or may not be associated with endometriosis in other sites. Usually, this condition is seen in females in their 4 th–5th decades of life. Clinically, they present with pain abdomen. The endometriotic cyst can be large in size with irregular lining and with areas of hemorrhage. [4] Case Report A 37‑year‑old female, P2 L2 presented with the clinical history of gradual swelling of abdomen and loss of appetite for 5 months. She had no history of surgery, including cesarean section. Ultrasonography was reported as left ovarian malignancy. Her CA‑125 level was 116 U/ml (<35 U/ml). Computed tomography imaging showed a large abdominopelvic cystic lesion with multiple internal enhancing septations. The cyst was displacing the uterus posteriorly and bowel loops superiorly. Bilateral ovaries were seen separately [Figure 1a and b]. She underwent laparoscopic debulking of the tumor along with hysterectomy and bilateral salpingo‑oophorectomy. Intraoperatively, there was a large cystic lesion covering the whole of the abdominal cavity, densely adhered to mesentery. Grossly, the cyst was measuring 20 cm × 17 cm and was attached to the left ovary, left fallopian tube, and posterior aspect of the uterine wall [Figure 1c]. Histopathology of the cyst showed many endometrial glands lined by cuboidal epithelium surrounded by a rim of the compact endometrial stroma [Figure 1d]. The rest of the stroma was edematous. Immunohistochemistry done with CD10 and progesterone receptor (PR) highlighted the endometrial stroma. The glandular lining was positive for CK7 [Figure 1e and f]. The final diagnosis given was endometriotic cyst. There were no areas of necrosis or increased mitotic activity. She had an uneventful postoperative period.

By definition, the presence of functioning endometrial glands and stroma outside the uterine cavity is known as endometriosis. The diagnostic criteria of endometriosis Submitted: 13‑Aug‑2019 Revised: 18‑Oct‑2019 Accepted: 21‑Dec‑2019 Published: 11‑Apr‑2020 Access this article online Website: www.ccij‑online.org DOI: 10.4103/ccij.ccij_74_19 Quick Response Code: Patnayak, et al.: Endometriotic cyst Clinical Cancer Investigation Journal | Volume 9 | Issue 1 | January-February 2020 23 include the presence of two of the following three features outside of the uterus: endometrial glands, endometrial stroma, and hemosiderin‑laden macrophages. Endometriosis is a fairly common condition. It is estimated to affect approximately 6%–10% of the reproductive age group females. [1] The macroscopic indicators of the endometriosis can manifest themselves in various ways such as a few petechial, vesicular, hemorrhagic, powder‑like implants or serous or clear vesicular structures or intraperitoneal adhesions attached to both ovaries, the pouch of Douglas, and uterosacral ligaments. In 40%–60% of the patients, endometriosis is accompanied by ovarian endometrioma.[2] The exact cause and pathogenesis of endometriosis are not clear. There are several theories regarding the pathogenesis of endometriosis. One theory suggests that through retrograde menstruation, viable endometrial cells are transported to the peritoneal cavity. Another theory is that of transtubal dissemination of endometrial tissue, which is also considered as the most common route of spread. One more theory is the iatrogenic deposition of endometrial tissue following any gynecological surgery and cesarean sections.[1] Our patient did not have any such history. Goumenou et al . have described a case of endometriosis‑associated with massive ascites, pleural effusion, and extremely elevated CA‑125 mimicking advanced ovarian cancer. [5] The patient did not have ascites or pleural effusion. In the case of endometriosis, the frozen‑section analysis should be performed during the surgery to rule out the possibility of malignancy associated with endometriosis. [3] However, in the present case, the intraoperative frozen section was not performed. In our case, the findings suggestive of malignancy were the size, which was huge, measuring 20 cm. The level of CA‑125 was elevated. It was attached to the left ovary, left fallopian tube, and posterior aspect of the uterine wall. The presence of endometrial glands and stroma along with immunochemistry, which showed CD10 and PR positivity in the endometrial stroma and CK7 positivity in the endometrial gland, established the diagnosis of the endometriotic cyst. Endometriotic cyst in retroperitoneal location is rare, and only a few cases have been reported in the English literature.[6‑9] Recently, Pang et al . have described a case of mass‑like endometriosis on the surface of the uterus mimicking ovarian malignancy.[3] Very rarely endometrioid adenocarcinoma can arise from endometriosis.[10] The present case is a benign one of the endometriotic cyst.

Although relatively rare in retroperitoneal location, a diagnosis of endometriotic cyst should be considered in the differential diagnosis of cysts in premenopausal women. In our case, the histopathological diagnosis of the endometriotic cyst was confirmed with the immunohistochemical staining. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

1. Raffi F, Amer S. Endometriosis. Obstet Gynaecol Reprod Med 2011;21:112‑7. Figure 1: (a and b) Computed tomography imaging of a large abdomino-pelvic cystic lesion with multiple internal enhancing septations. (c) Gross of huge cyst attached to left ovary, left fallopian tube and posterior aspect of the uterine wall. (d) Histopathology showing endometrial glands and stroma (H and E, ×200). (e) Immunohistochemistry showing cytoplasmic positivity for CD10 in endometrial stroma (immunohistochemistry, ×400). (f) Immunohistochemistry showing nuclear positivity for progesterone receptor in endometrial glands and stroma (immunohistochemistry, ×100) d c b f a e Patnayak, et al.: Endometriotic cyst 24 Clinical Cancer Investigation Journal | Volume 9 | Issue 1 | January-February 2020 2. Vercellini P, Fedele L, Aimi G, De Giorgi O, Consonni D, Crosignani PG. Reproductive performance, pain recurrence and disease relapse after conservative surgical treatment for endometriosis: The predictive value of the current classification system. Hum Reprod 2006;21:2679‑85. 3. Pang L, Shi H, Wang T, Zhu L, Lang J, Fan Q, et al. Endometriosis on the surface of the uterus mimicking a malignant tumor: A case report with literature review. Medicine (Baltimore) 2019;98:e15741. 4. Kurman RJ, Ellenson LH, Ronnett BM. Blaustein’s Pathology of the Female Genital Tract. 6 th ed. Switzerland: Springer International Publishing; 2011. 5. Goumenou A, Matalliotakis I, Mahutte N, Koumantakis E. Endometriosis mimicking advanced ovarian cancer. Fertil Steril 2006;86:219.e23‑5. 6. Rana S, Stanhope RC, Gaffey T, Morrey BF, Dumesic DA. Retroperitoneal endometriosis causing unilateral hip pain. Obstet Gynecol 2001;98:970‑2. 7. Lolis ED, Carvounis EE, Vasilikostas G, V oros D. Subhepatic retroperitoneal endometrioma: Report of a case. Gynecol Endocrinol 2007;23:479‑81. 8. Lorente Poyatos R, Palacios Pérez A, Bravo Bravo F, López Caballero FJ, Bouhmidi A, Huertas Nadal C, et al . Rectosigmoid endometriosis with lymph node involvement. Gastroenterol Hepatol 2003;26:23‑5. 9. Gouthaman S, Kaundinya K. Retroperitoneal endometriotic cyst mimicking a tumor. Gynecol Obstet 2015;5: 293. 10. Kawate S, Takeyoshi I, Ikota H, Numaga Y , Sunose Y , Morishita Y . Endometrioid adenocarcinoma arising from endometriosis of the mesenterium of the sigmoid colon. Jpn J Clin Oncol 2005;35:154‑7.