A 45-year-old woman with a long-standing 6 cm ovarian endometrioma undergoes cystectomy. Histopathology unexpectedly shows malignant transformation. Which is the MOST common histological subtype arising in an endometrioma?
- A Serous carcinoma
- B Mucinous carcinoma
- C Clear cell carcinoma ✓
- D Granulosa cell tumour
Correct answer: C. Clear cell carcinoma
Explanation
Endometriosis-associated ovarian cancers are predominantly clear cell carcinoma and endometrioid carcinoma, both arising through the oestrogen-driven pathway. Clear cell carcinoma is the single most frequently reported subtype within endometriomas. Serous carcinoma follows the p53-mutant high-grade pathway and does not arise from endometriosis. Granulosa cell tumour is a sex cord stromal neoplasm unrelated to endometriotic epithelium. Risk of transformation is roughly 1%.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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