Background: Brenner tumors are rare ovarian neoplasms that often coexist with other epithelial tumors, most commonly mucinous cystic neoplasms. The association of Brenner tumors with endometriosis is unusual and not well-documented in the literature. Case presentation: We describe the case of a 64-year-old postmenopausal woman presenting with abnormal uterine bleeding and a left adnexal mass. Histopathologic examination revealed the synchronous presence of a benign Brenner tumor, mucinous cystadenoma, and a microscopic focus of endometriosis, all within the same ovary. Discussion: The simultaneous occurrence of these three lesions is highly unusual. A potential shared histogenetic origin has been proposed for Brenner and mucinous tumors, while the coexistence of endometriosis raises further questions regarding hormonal or microenvironmental influences. Thorough histopathologic and immunohistochemical evaluation is essential in such complex presentations. Conclusion: This case underscores the importance of comprehensive pathologic assessment in ovarian masses, especially when multiple histologic components are present. Recognition of rare associations can prevent misdiagnosis and guide appropriate clinical management.
Ramezani et al. (2026) studied this question.