A 35-year-old woman has a thyroid nodule. Fine-needle aspiration shows cells with nuclear grooves, optically clear nuclei ('Orphan Annie eye'), and nuclear pseudo-inclusions. The most likely diagnosis is:

• A Papillary carcinoma of thyroid ✓
• B Follicular carcinoma of thyroid
• C Medullary carcinoma of thyroid
• D Anaplastic carcinoma of thyroid

Explanation

Papillary thyroid carcinoma (PTC) is diagnosed on the basis of characteristic nuclear features: optical clearing (ground-glass or 'Orphan Annie eye' nuclei), nuclear grooves, and intranuclear pseudo-inclusions (cytoplasmic invaginations). These nuclear features are sufficient for diagnosis even on cytology and remain even if no papillae are present. BRAF V600E is the most common somatic mutation in 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.