A 6-year-old boy develops headaches and ataxia. MRI shows a midline posterior fossa mass. Biopsy reveals a small round blue cell tumor with Homer-Wright rosettes. Which molecular subgroup of this tumor carries the best prognosis?
- A WNT-activated ✓
- B SHH-activated
- C Group 3
- D Group 4
Correct answer: A. WNT-activated
Explanation
The tumor is medulloblastoma. The WNT-activated subgroup, often with CTNNB1 mutations, has an excellent prognosis. Group 3 medulloblastomas have a poor prognosis, while SHH-activated and Group 4 have intermediate outcomes. Homer-Wright rosettes are a classic histological feature of medulloblastoma.
Reference: WHO Classification of Tumours of the Central Nervous System, 5th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.