A Retroperitoneal Cyst Masquerading as a Para-ovarian Cyst in a Postmenopausal Woman.

Peritoneal inclusion cysts are rare mesothelium-lined abdominopelvic cysts occurring in perimenopausal women, first described by Mennemeyer and Smith in 1979.[] They are commonly misdiagnosed as ovarian tumors. A 56-year-old, P2L2, menopausal woman presented with lower backache and dysuria for 1 month. She had previous cesarean, with family history of breast cancer. Pelvic examination was unremarkable. Transvaginal and transabdominal ultrasound showed a large, anechoic cystic lesion of 10 cm close to the right adnexa, without solid components or color flow [Figure 1]. Total laparoscopic hysterectomy with bilateral salpingo-oophorectomy and excision of the right para-ovarian cyst was planned. Laparoscopy showed a normal uterus, fallopian tubes, and ovaries with a large 10-cm retroperitoneal cyst over the right pelvic side wall [Figure 2]. The cyst was enucleated after isolating the right ureter, and the content was serous fluid [Figure 3]. Histopathology confirmed benign cystic mesothelioma [Figure 4]. One-year follow-up showed no evidence of recurrence. Benign cystic mesothelioma is a rare tumor arising from the abdominal peritoneum. Mesothelial tumors can be benign cystic, adenomatoid, or malignant. Classically, they present as large multi-cystic masses. Typical symptoms are abdominal distention, tenderness, ascites, nausea, and constipation.[] It can mimic conditions such as ovarian malignancies and cystic lymphangioma and can pose a diagnostic challenge. Histopathology is confirmative. The presence of long slender apical microvilli and the hobnailed appearance of the cells are some of the distinguishing features.[] Pathogenesis remains unclear. It may be associated with endometriosis, pelvic inflammatory disease, and previous abdominal surgeries.[] The treatment is usually surgical resection. Recurrence is possible, and therefore, follow-up after surgery is recommended. These tumors may have local recurrence and can even occur many years later. It has been proposed that benign cystic mesothelioma behaves more like a borderline lesion. Rarely, it may transform into aggressive diffuse malignant mesothelioma.[] Therefore, periodic follow-up is warranted. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. REFERENCES - 1. Rapisarda AM, Cianci A, Caruso S, Vitale SG, Valenti G, Piombino E, et al Benign multicystic mesothelioma and peritoneal inclusion cysts: Are they the same clinical and histopathological entities? A systematic review to find an evidence-based management Arch Gynecol Obstet. 2018;297:1353–75 - 2. Wang TB, Dai WG, Liu DW, Shi HP, Dong WG. Diagnosis and treatment of benign multicystic peritoneal mesothelioma World J Gastroenterol. 2013;19:6689–92 - 3. Elbouhaddouti H, Bouassria A, Mouaqit O, Benjelloun el B, Ousadden A, Mazaz K, et al Benign cystic mesothelioma of the peritoneum: A case report and literature review World J Emerg Surg. 2013;8:43 - 4. Baddoura FK, Varma VA. Cytologic findings in multicystic peritoneal mesothelioma Acta Cytol. 1990;34:524–8 - 5. Thawait SK, Batra K, Johnson SI, Torigian DA, Chhabra A, Zaheer A. Magnetic resonance imaging evaluation of non ovarian adnexal lesions Clin Imaging. 2016;40:33–45 - 6. González-Moreno S, Yan H, Alcorn KW, Sugarbaker PH. Malignant transformation of “benign” cystic mesothelioma of the peritoneum J Surg Oncol. 2002;79:243–51