Primary glioblastoma multiforme of cerebellar hemispheres in adults is a rare condition. Most of them result from dedifferentiation of astrocytoma to glioblastoma. We present two cases of unusual de novo cerebellar glioblastomas, one of which is the giant-cell variant. We review their clinical behaviour with conventional MR imaging features and discuss the key findings that can lead to the correct diagnosis in sight of new MR imaging technologies.

Keywords: glioblastoma multiforme, posterior fossa, cerebellum, magnetic resonance imaging