During laparotomy for an ovarian cyst in a 34-year-old woman, the surgeon finds a firm yellow-white solid ovarian tumour. Frozen section shows islands of transitional-type epithelium with nuclei bearing longitudinal grooves, embedded in dense fibrous stroma. What is the diagnosis?

• A Fibroma
• B Thecoma
• C Brenner tumour ✓
• D Metastatic transitional cell carcinoma

Explanation

Brenner tumour is composed of urothelial-like (transitional) epithelial nests within abundant fibromatous stroma, and the characteristic coffee bean nucleus with its central longitudinal groove clinches the diagnosis. It is almost always benign and is notably associated with an adjacent mucinous cystadenoma in up to one third of cases. A pure fibroma lacks epithelial nests, which distinguishes option A.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.