Exophytic glioblastoma arising from the cerebellar tonsil is an extremely rare variant within the possible anatomical presentations of the glioblastoma multiforme (GBM). We report the case of a 55-year-old woman who presented with a tumor located at the cranio-cervical junction with compression of the medulla oblongata and consecutive hydrocephalus. Due to the radiological presentation, the first tentative diagnosis was a meningioma. The tumor was microsurgically removed. Histopathological examination of the tumor revealed a GBM WHO IV. The patient underwent a postoperative percutaneous radiotherapy and concomitant chemotherapy with temozolomide. GBM should be also considered in the differential diagnosis of cerebellar tumors.