Borderline serous ovarian neoplasm: case report of a diagnostic challenge in intraoperative frozen sections

Surface epithelial tumors of the ovary account for 25% of all ovarian neoplasms. When composed predominantly of fibrous stroma, with glands and cysts forming a minor component, their appearance on imaging is often complex; cystic- to solid-appearing masses often raise suspicion of a malignant tumor. An accurate frozen histopathological diagnosis of a benign cystadenofibroma of this tumor can facilitate appropriate surgical management. However, it is equally important to diagnose areas of borderline changes/malignancy arising in these tumors, particularly when large or complex surface and inner papillary areas with multilayering or stratification are seen microscopically. We present here a case of bilateral complex ovarian mass in a 68-year-old woman, which was equivocal for malignancy on radiology, per operative gross examination as well as on frozen section evaluation. It was finally diagnosed as a borderline serous tumor (BOT) in a cystadenofibroma on histopathological examination.