Choroid plexus cyst in a dog.

A 6-year-old male Doberman Pinscher had a 2-month history of dysequilibrium. Lesion localization was determined to be the cerebellomedullary pontine angle. In computed tomographic images, a well-defined, circular, hypoattenuating mass was visible at the cerebellomedullary pontine angle. The lesion, which was isoattenuating to cerebrospinal fluid, was 4 × 8 mm in diameter. Peripheral ring enhancement was evident after contrast medium administration. A choroid plexus cyst was diagnosed histopathologically.