Bilateral primary ovarian clear cell carcinoma in a multiparous perimenopausal woman

Primary ovarian clear cell carcinoma (OCCC) is a rare subtype of epithelial ovarian carcinoma (EOC), accounting for 5–10% of EOCs in the U.S., with a higher prevalence in East Asia. It is characterized by clear cells forming solid, tubular, or papillary patterns, and presents diagnostic challenges due to its resemblance to renal clear cell carcinomas. Typically affecting nulliparous postmenopausal women, OCCC is associated with high recurrence rates and low sensitivity to platinum-based chemotherapy. We report a case of bilateral primary OCCC in a 45-year-old multiparous woman with no history of endometriosis. She presented with lower abdominal pain and swelling persisting for 7–8 months. Imaging revealed a large, heterogeneous abdominopelvic mass. Surgery included total abdominal hysterectomy with bilateral salpingo-oophorectomy. Histopathological and immunohistochemical analyses confirmed bilateral OCCC, with positive staining for AMACR, Napsin A, and PAX8, and negative results for WT1, ER, and PR. This case highlights the importance of thorough diagnostic evaluation in atypical presentations. The postoperative course was uneventful, and she subsequently received adjuvant therapy.