The Bethesda System for Reporting Thyroid Cytopathology classifies FNA results into six categories. A Category IV (follicular neoplasm/suspicious for follicular neoplasm) result carries an approximate malignancy risk of:
- A 1-4%
- B 45-60%
- C 10-40% ✓
- D 70-90%
Correct answer: C. 10-40%
Explanation
Bethesda Category IV (follicular neoplasm or suspicious for follicular neoplasm) carries a malignancy risk of approximately 10-40% (revised estimates from Bethesda 2023 place it around 25-40%). Because FNA cannot distinguish follicular adenoma from follicular carcinoma (diagnosis requires histological demonstration of capsular or vascular invasion), diagnostic hemithyroidectomy is recommended. This contrasts with Category VI (malignant, ~97-99% risk) and Category II (benign, ~2-4% risk).
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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