A 6-year-old girl presents with headache and vomiting. MRI shows an intraventricular mass at the level of the fourth ventricle. Histology shows uniform cells forming rosettes around central blood vessels with an anuclear zone between the nuclei and the vessel wall. This finding is characteristic of:

• A Verocay body of schwannoma
• B Homer Wright rosette of neuroblastoma
• C Flexner-Wintersteiner rosette of retinoblastoma
• D Perivascular pseudorosette of ependymoma ✓

Explanation

Ependymomas characteristically form perivascular pseudorosettes, where tumor cell processes taper toward a central vessel leaving an anuclear zone, and true ependymal rosettes surrounding a central lumen. Homer Wright rosettes surround a central mesh of neuropil, not a vessel, and are seen in medulloblastoma and neuroblastoma. Flexner-Wintersteiner rosettes occur in retinoblastoma, and Verocay bodies are palisaded nuclear arrays in schwannoma.

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.