Papillary thyroid carcinoma (PTC) is characterised by the nuclear features of Orphan Annie eye nuclei, nuclear grooves, and nuclear pseudoinclusions. The most common molecular alteration driving PTC is:
- A BRAF V600E point mutation (activating MAPK pathway) ✓
- B RET/PTC rearrangement (constitutive RET kinase activation)
- C RAS point mutation
- D PAX8-PPARgamma translocation
Correct answer: A. BRAF V600E point mutation (activating MAPK pathway)
Explanation
BRAF V600E (valine to glutamate at codon 600) is the most common driver mutation in PTC, found in ~50-60% of cases, constitutively activating the MAPK/ERK proliferative pathway. It is associated with more aggressive behavior and lymph node metastases. RET/PTC rearrangements occur in ~20% of sporadic PTCs and are more common in radiation-induced PTCs. RAS mutations are more associated with follicular variant PTC and follicular carcinoma. PAX8-PPARgamma translocation is characteristic of follicular thyroid 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.