LAUSR

Background: Endometriosis affect pelvic organs in ~10% of cases. The question of endometriosis being a precancerous lesion versus an incidental association with adnexal (fallopian tubes and ovaries) tumors is a point of debate. This study aimed to determine the frequency of adnexal tumors in cases with histologically proven endometriosis of adnexal structures at our institution. Methods: A retrospective chart review of patients diagnosed with adnexal endometriosis from 2013-2017 was performed. Patients’ age, demographic data, and associated ipsilateral benign or malignant adnexal tumors were obtained from the pathology notes. Results: 151 cases with a histologically verified endometriosis of fallopian tubes and/or ovaries were retrieved. The average age of the patients was 42 years (range of 22-78 years). The race/ethnic groups of the patients were white, black, and others in 120 (79%), 17 (11%) and 14 (9%), respectively. Associated malignant tumors were identified in 8 (5.3%) cases while 10 (6.6%) cases were found to have benign neoplasms in the ipsilateral site of endometriosis. The malignant tumors were endometrioid adenocarcinoma (n=4), high-grade serous carcinoma (n=3), and clear cell carcinoma (n=1). The benign neoplasms were serous cystadenoma/ cystadenofibroma (n=7) and seromucinous tumors (n=3). Conclusions: The incidence of malignant neoplasms, especially endometrioid and high-grade serous carcinoma, is relatively high in cases with histologically verified endometriosis in our experience. Among benign tumors, serous cystadenoma and seromucinous neoplasms appear to be frequently associated with endometriosis. More studies are needed to further highlight the significance of adnexal endometriosis in causation of malignant and benign adnexal tumors. Citation Format: Mohamed Mokhtar Desouki. Adnexal tumors associated with endometriosis: Experience from an academic institution. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B68.