A 45-year-old woman with a known 8 cm ovarian endometrioma present for 15 years now has a rapidly enlarging pelvic mass with rising CA-125. Histopathology of the excised cyst shows malignant transformation of the endometrioma. Which histological subtype is MOST classically associated?

• A Granulosa cell tumour
• B High-grade serous carcinoma
• C Mucinous borderline tumour
• D Clear cell carcinoma ✓

Explanation

Malignant transformation occurs in a small proportion of long-standing endometriomas, and the two characteristic subtypes are clear cell carcinoma and endometrioid carcinoma. High-grade serous carcinoma arises from the fallopian tube fimbriae via p53 mutation, mucinous tumours are typically gastrointestinal in origin, and granulosa cell tumours arise from sex cord stromal cells, not from endometriotic epithelium.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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