A 30-year-old woman presents with a thyroid nodule. Fine-needle aspiration cytology (FNAC) is reported as Bethesda Category V (suspicious for malignancy). Which molecular marker testing, if positive, would most strongly indicate papillary thyroid carcinoma and guide surgical planning?

• A RAS point mutation (HRAS/KRAS/NRAS)
• B PAX8-PPARG rearrangement
• C BRAF V600E mutation ✓
• D RET-PTC rearrangement only

Explanation

BRAF V600E mutation is detected in approximately 45–60% of papillary thyroid carcinomas (PTC) and is highly specific for PTC when found in an indeterminate or suspicious nodule. Its presence at molecular testing of FNA material significantly increases the probability of PTC and often prompts total thyroidectomy rather than diagnostic hemithyroidectomy. RAS mutations are associated with follicular neoplasms and RAS-like PTC variants; PAX8-PPARG with follicular carcinoma; RET-PTC rearrangements confirm PTC but are less common than BRAF.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.