Cerebellar low-grade oligoastrocytoma presenting with subarachnoid haemorrhage.

Subarachnoid haemorrhage (SAH) associated with intra-axial tumours is extremely uncommon and is usually seen in association with intratumoural bleed. Tumours located near the ventricle or subarachnoid spaces have a higher propensity for SAH compared to intraparenchymal lesions. Low-grade tumours rarely demonstrate any evidence of bleed on imaging. Oligoastrocytomas of the posterior fossa are rare tumours in adults and their presentation with intratumoural haemorrhage and SAH is unknown. We report a unique case of cerebellar low-grade oligoastrocytoma that mimicked a tentorial-based extraaxial lesion on imaging and presented with SAH. Susceptibility-weighted magnetic resonance imaging is a useful imaging modality to demonstrate blood within and outside the tumour.