A 25-year-old presents with hydrocephalus. MRI shows an intraventricular mass attached to the septum pellucidum. Histology reveals uniform round cells with perivascular pseudorosettes and synaptophysin positivity. Which molecular feature is typically absent in this tumor?

• A Intraventricular location
• B Synaptophysin expression
• C Perivascular pseudorosettes
• D IDH1 mutation ✓

Explanation

The tumor is central neurocytoma, a neuronal neoplasm. It expresses synaptophysin and shows perivascular pseudorosettes, but lacks IDH1 mutations, which are characteristic of diffuse gliomas. Central neurocytomas are WHO grade 2 tumors with a favorable prognosis after resection.

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.