Cerebral metastasis of transmissible venereal tumor after effective chemotherapy in a dog

Abstract

A male mixed breed street dog (age unknown) presented with an ocular mass and multiple ulcerated subcutaneous nodules on both hind limbs which bled easily when touched. Inspection of the genital organs revealed that no masses were present. The ocular mass and nodules were diagnosed as a transmissible venereal tumor (TVT) by fine-needle aspiration cytology. The total remission of the tumor was achieved after 5 applications of vincristine sulfate. The dog was adopted during the remission period, but 5 months after adoption he developed neurological signs and died. The necropsy revealed a mass located in the trunk of the corpus callosum of the right hemisphere of the brain. The cytological, histological, and PCR findings of the brain mass were consistent with a TVT. These findings highlight the need to consider the aggressive metastatic potential of canine TVT, even after apparently effective chemotherapy.