JVD 2020 #4 Diagnosis and Management of an Oronasal Fistula Secondary to Nasal Transmissible Venereal Tumor in a Dog; Thatcher Flashcards
What is canine transmissible venereal tumor (CTVT)?
Naturally occuring, contagious round cell neoplasm that commonly affects stray and wild dogs that are in close contact with one another and exhibit sexual behaviors. Enzootic in tropical and subtropical regions of the world esp in areas with large pop of stray dogs.
What is the usual appearance of CTVT tumor?
Exophytic, pedunculated, nodular, or multi-lobular and mainly affects the external genitalia, though it can be on the adjacent skin or less commonly the oral, nasal or conjunctival mucosa.
What is the histologic appearance of CTVT? What can it resemble?
Highly cellular neoplasm of round cells that closely resemble lymphoma, histiocytoma or other pleomorphic round cell tumors. Mixed infiltrates of inflammatory cells are commonly seen.
There is no specific immunohistochemical markers (antigens) for CTVT.
What immunohistochemistry tests were used? (IHC)
The neoplastic cells were negative for IHC for CD3 and CD20, pancytokeratin, chromogranin and melan A.
These are markers for lymphocytes, melanocytes, mast cells, epithelial cells and neuroendocrine cells.
Where did the male dog originate?
Mexico, and was transported to Canada for adoption.
How was the CTVT treated?
6 treatments of vincristine sulfate after oncologic staging.
When was the ONF surgically treated, and how?
2 weeks following the final chemotherapy treatment and 3 weeks following 2nd CT scan showing absence of soft tissue mass in the oral and nasal cavities. A U-shaped transposition flap with a small triangle of tissue (Burow’s triangle) removed at caudal aspect to facilitate movement over the defect. Care was takent to preserve the major palatine artery in the flap.
Transposition U-flap used for closure of the ONF
What is the most common site for extragenital CTVT?
The nasal cavity (sniffing/licking behavior)
