A 57-year-old woman presented with a 4-month history of positional vertigo provoked by rolling to the left in bed. The patient was treated unsuccessfully by 3 clinicians for benign paroxysmal positional vertigo. The Dix-Hallpike maneuvre to both sides revealed persistent upbeating nystagmus with no latency. Supine roll test revealed persistent apogeotropic nystagmus to the left and persistent upbeating torsional nystagmus to the right (video). Neurologic examination, including detailed cerebellar testing, was unremarkable. A cranial MRI revealed a 21 x 20 x 38 mm lobulated heterogeneously enhancing fourth ventricular tumor (figures 1 and 2). The patient underwent a midline posterior fossa craniotomy for resection of the lesion. The histopathologic examination of the specimen confirmed a WHO grade II ependymoma. In this case, vertigo and positional nystagmus were the sole presenting features of CNS pathology.