Multiple metastases of a transmissible venereal tumor in a dog

ABSTRACT

Background: Transmissible venereal tumor (TVT) is a common contagious neoplasm in dogs that spreads through coitus.Extra-genital presentations of this tumor are frequent and usually develop through implantation of neoplastic cells onexposed mucosae. TVT metastasis is rare, and when it happens it’s usually affecting regional lymph nodes and adjacentcutaneous tissue.Case A female mixed breed dog, with estimated age of 7 to 11 months old, was rescued from the streets and taken to aveterinary clinic in the city of Porto Alegre, RS. The animal had multiple nodules on its body, vulva, ocular mucosa, andgingiva, along with signs of malnutrition and apathy. Cytological examination of the nodules and vulva was done andyielded a cytologic picture compatible with TVT. Weakly treatment with 0,3mg/m² vincristine sulphate was used untilclinical cure was noted. Approximately two weeks after clinical cure, the dog showed a blue colored eye and was referredfor ophthalmological, where it was diagnosed with vision loss due to glaucoma secondary to a neoplasm. The eye wasthen removed and sent for histopathological evaluation. Histopathology of the eye was compatible with TVT diagnosis.One month after enucleation the animal display dispenia, pain, aggressiveness and epistaxis. The animal was euthanizedand submitted for post-mortem evaluation. At necropsy there was a well-defined grayish-white, nodule near the thalamus.Similar nodules were also found on the lung, and anterior chamber of the eye. Histologically, all the nodules were compatible with TVT. Immunohistochemical examination was done, with the neoplastic cells being positive for vimentin andnegative for cytokeratin, CD79a, CD3 and CD117. Based on the post-mortem examination and clinical history, diagnosisof TVT...