Frozen Section Diagnosis of Ovarian Epithelial Tumors: Diagnostic Pearls and Pitfalls.

CONTEXT.—: Epithelial tumors of the ovary are one of the most frequently encountered gynecologic specimens in the frozen section laboratory. The preoperative diagnostic workup of an ovarian mass is typically limited to imaging studies and serum markers, both of which suffer from low sensitivity and specificity. Therefore, intraoperative frozen section evaluation is crucial for determining the required extent of surgery, that is, cystectomy for benign tumors, oophorectomy or limited surgical staging for borderline tumors in younger patients to preserve fertility, or extensive staging procedure for ovarian carcinomas. Ovarian epithelial tumors may exhibit a wide range of morphologic patterns, which often overlap with each other and can mimic a variety of other ovarian nonepithelial neoplasms as well. A combination of careful gross examination, appropriate sampling and interpretation of morphologic findings, and familiarity with the clinical context is the key to the accurate frozen section diagnosis and successful intraoperative consultation. OBJECTIVE.—: To review the salient frozen section diagnostic features of ovarian epithelial tumors, with special emphasis on useful clinicopathologic and morphologic clues and potential diagnostic pitfalls. DATA SOURCES.—: Review of the literature and personal experience of the author. CONCLUSIONS.—: Frozen section evaluation of ovarian tumors continues to pose a significant diagnostic challenge for practicing pathologists. This review article presents detailed discussions of the most common clinical scenarios and diagnostic problems encountered during intraoperative frozen section evaluation of mucinous, serous, endometrioid, and clear cell ovarian tumors.