A 9-year-old boy presents with headache, bitemporal hemianopia, and short stature. Imaging shows a suprasellar cystic mass with calcification. Biopsy shows cords of squamous epithelium with peripheral palisading, wet keratin, and nuclear beta-catenin accumulation. What is the diagnosis and its characteristic molecular finding?

• A Adamantinomatous craniopharyngioma with activating CTNNB1 (beta-catenin) mutation ✓
• B Rathke cleft cyst with ciliated epithelium
• C Papillary craniopharyngioma with BRAF V600E mutation
• D Germinoma with OCT3/4 positivity

Explanation

Adamantinomatous craniopharyngioma occurs in children, is suprasellar and cystic with calcification, and shows palisaded squamous epithelium, wet keratin, and aberrant nuclear beta-catenin from activating CTNNB1 mutations. The papillary variant occurs in adults, lacks calcification and wet keratin, and instead carries BRAF V600E mutations, which is the fact that kills the closest distractor. Germinoma is a pure germ cell tumor positive for OCT3/4 and PLAP.

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.