Benign mixed epithelial ovarian tumor with mucinous, serous, and transitional components: a rare case report

Benign epithelial ovarian tumors are among the most common ovarian neoplasms, with mucinous, serous, and transitional types representing major subgroups. However, the coexistence of multiple epithelial components within a single ovarian lesion is exceedingly rare. We report the case of a multiparous woman presenting with progressive abdominal distension caused by a large ovarian cyst. Imaging revealed a giant, well-circumscribed cystic mass, which was surgically excised. Histopathological evaluation demonstrated a predominantly mucinous cystadenoma with foci of serous and transitional (Brenner-like) epithelial differentiation, without borderline or malignant features. This case represents a rare example of a benign mixed epithelial ovarian tumor and highlights the importance of thorough histopathological examination to avoid misdiagnosis and to better understand mixed Müllerian epithelial differentiation.