A 40-year-old woman presents with a thyroid nodule. FNAC shows papillary carcinoma. Histology confirms orphan Annie eye nuclei, nuclear grooves, and psammoma bodies. The most common oncogenic driver in sporadic papillary thyroid carcinoma is:

• A RAS mutation
• B PTEN mutation
• C RET/PTC rearrangement or BRAF V600E mutation ✓
• D TP53 mutation

Explanation

BRAF V600E mutation is the most common single alteration in sporadic papillary thyroid carcinoma (PTC), found in approximately 45–60% of cases; RET/PTC chromosomal rearrangements are the second most common, particularly in radiation-associated cases. Both activate the MAPK signalling pathway. RAS mutations are more common in follicular carcinoma and the follicular variant of PTC; PTEN loss is associated with follicular carcinoma in PHTS; TP53 mutation is characteristic of poorly differentiated and anaplastic carcinoma.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.