A 55-year-old man presents with progressive headache, papilloedema, and gait ataxia. MRI shows a posterior fossa midline mass with cystic component and a mural nodule. The nodule enhances brightly. Histology shows a highly vascular tumour with Weibel-Palade bodies on electron microscopy and negative for S100 and GFAP. The most likely diagnosis is:
- A Haemangioblastoma ✓
- B Pilocytic astrocytoma
- C Medulloblastoma
- D Ependymoma
Correct answer: A. Haemangioblastoma
Explanation
Haemangioblastoma is a benign (WHO grade I) highly vascular tumour of the posterior fossa, classically presenting as a cystic lesion with an enhancing mural nodule on MRI. The nodule contains stromal cells that produce VEGF, explaining the dense vascularity. Weibel-Palade bodies (rod-shaped organelles in endothelial cells) confirm vascular endothelial differentiation. Haemangioblastoma stains negative for GFAP and S100. It is associated with Von Hippel-Lindau (VHL) syndrome in ~25% of cases. Pilocytic astrocytoma is GFAP-positive.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.