A 14-year-old boy has bitemporal hemianopia and growth failure. MRI shows a suprasellar cystic mass with calcification. Histology reveals nests and cords of squamous epithelium with peripheral palisading, 'wet keratin' nodules, and stellate reticulum. Nuclear accumulation of which protein drives this tumour?

• A Beta-catenin ✓
• B Alpha-fetoprotein
• C Chromogranin A
• D S-100 protein

Explanation

Adamantinomatous craniopharyngioma arises from remnants of Rathke pouch, occurs in children, and shows palisaded squamous epithelium, stellate reticulum, wet keratin and calcification. Activating mutations of CTNNB1, the gene encoding beta-catenin, lead to nuclear accumulation of beta-catenin, which is the diagnostic molecular finding. Chromogranin marks neuroendocrine cells, S-100 marks neural and melanocytic lesions, and AFP relates to yolk sac tumours.

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.