A probable cavernoma in the medulla oblongata presenting only as upbeat nystagmus.

A cavernoma is a vascular malformation in the central nervous system. Brainstem cavernoma are relatively common and induce variable neurological symptoms. A 19-year-old woman visited our hospital with complaints of continuous dizziness. On a neurological examination, continuous conjugated upbeat nystagmus was observed in the primary position of gaze. A brain CT scan and MRI showed focal hemorrhagic signals in the central caudal medulla caused by a cavernoma. The spontaneous upbeat nystagmus disappeared gradually. To our knowledge, this is the first report of a probable cavernoma in the medulla oblongata presenting with upbeat nystagmus only.