Which histological feature is considered characteristic of papillary carcinoma of the thyroid?
- A Amyloid stroma derived from calcitonin-producing cells
- B Psammoma bodies within the tumour ✓
- C Sheets of atypical follicular cells with capsular invasion
- D Marked anaplasia with giant cells and frequent mitoses
Correct answer: B. Psammoma bodies within the tumour
Explanation
Psammoma bodies, concentric lamellated calcifications, are a classic feature of papillary thyroid carcinoma and support the diagnosis when seen in cytology or histology. The nuclei show optically clear 'Orphan Annie eye' appearance, grooves, and intranuclear pseudoinclusions. Amyloid stroma is the hallmark of medullary carcinoma, capsular or vascular invasion defines follicular carcinoma, and marked anaplasia with giant cells describes anaplastic carcinoma.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.