A 45-year-old woman presents with a painless neck mass. Fine-needle aspiration shows cells with oval nuclei, pale powdery chromatin, nuclear grooves, and occasional intranuclear inclusions. Psammoma bodies are identified. Which molecular alteration is most characteristically associated with this tumor?

• A RET/PTC rearrangement
• B PAX8-PPARG fusion
• C BRAF V600E point mutation ✓
• D TP53 mutation

Explanation

The cytologic features described — nuclear grooves, intranuclear pseudoinclusions, and psammoma bodies — are classic for papillary thyroid carcinoma (PTC). BRAF V600E is the most common somatic mutation in PTC, occurring in approximately 45–60% of cases. RET/PTC rearrangements also occur in PTC but are less frequent than BRAF mutation. PAX8-PPARG is characteristic of follicular carcinoma, not PTC.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.