Choroid plexus carcinoma in a dog.

Choroid plexus carcinoma was diagnosed in a 5-year-old female mixed breed dog which was euthanized due to progressive neurologic disease. Diagnosis of the tumour was based on gross and light microscopic findings following a complete necropsy. The chemical staining patterns in the case are compared with human choroid plexus tumours. The criteria for the distinction between benign and malignant variants of choroid plexus tumours are discussed.