Papillary thyroid carcinoma is the most common thyroid malignancy. The MOST specific histological diagnostic feature (even in metastatic lymph nodes) is:
- A Follicular architecture with colloid-filled spaces
- B Amyloid deposits in the stroma (Congo red positive)
- C Orphan Annie eye nuclei (ground-glass nuclei with nuclear grooves and pseudoinclusions) ✓
- D Capsular and vascular invasion without nuclear changes
Correct answer: C. Orphan Annie eye nuclei (ground-glass nuclei with nuclear grooves and pseudoinclusions)
Explanation
Papillary thyroid carcinoma is diagnosed primarily on nuclear features: 'Orphan Annie eye' nuclei (cleared/ground-glass appearance), nuclear grooves, and intranuclear pseudoinclusions (cytoplasmic invaginations). These features are present even in metastatic foci and define PTC regardless of architecture. Amyloid stroma with calcitonin is the hallmark of medullary thyroid carcinoma. Follicular carcinoma requires capsular/vascular invasion.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.