Three Cases of Exclusively Extragenital Canine Transmissible Venereal Tumor (cTVT)
AbstractBackground: Canine Transmissible Venereal Tumor (cTVT) is a neoplasia that affects mainly the genital organs of dogs, but can rich extragenital sites as well. It´s a tumor characterized microscopically by the presence of vacuolized round cells. Transmission occurs by implantation of these cells in non-affected tissues and the treatment is based on vincristine chemotherapy.
Cases: Case 1. A 5-year-old intact male Poodle, presenting an increase volume of nasal plane came for veterinary care at a private veterinary clinic. The animal had bilateral bloody nasal secretion and dyspnea. The external genitalia had no alterations. The cytological evaluation confirmed cTVT. Treatment with vincristine sulfate weekly showed a rapid response
with improvement of the respiratory condition, total remission of the mass and absence of neoplastic cells in cytology. Case 2. A 5-year-old mixed-breed canine bitch, weighing 6.7 kg, was brought to the State University of Santa Cruz Veterinary Hospital (UESC-VH), showing an increase volume in the nasal plan region, with complaints about sneezing, nasal bleeding,
respiratory distress with approximately 4 months of evolution. The owner informed that the mother of these female dog, that lived in the same environment, died a month before the beginning of clinical signs of the bitch of this case, and showed a reddish vaginal mass with intense bleeding. Intranasal exfoliative cytology showed moderately cellular sample compatible with cTVT. The treatment with vincristine sulphate for 6 weeks, showed completely remission of all clinical signs. Case 3. A 3-year-old mixed-breed male dog was brought to the UESC-VH with a reddish, friable mass located in the left eye. The citology confirmed the clinical suspicion of cTVT. After six weekly sessions of chemotherapy with vincristine sulfate, the tumor regressed and a new cytological evaluation was performed, without visible of tumor cells. By the end of the treatment, the dog was diagnosed with phitisis bulbi, and one year later, due to recurrent ulcerative keratitis, the enucleation was performed and the histopathological examination of the eye did not identify the presence of tumor cells.
Discussion: Two of the dogs cited in this report had freely streets access, without supervision of the owners, and they are likely to have contracted cTVT on one of those occasions. The animal’s care style acts as a risk factor for the development of neoplasia. Regarding the third animal, the close contact with another female dog, who had compatible vaginal cTVT
clinical signs was probably the factor that determined the transmission. None of the animals cited in this report had lesions on their external genitalia. The extragenital presentation may be attributed to the social behavior of licking and sniffing the genitalia of carrier animals, which may lead to the natural implantation of the viable cells of the cTVT into the ocular and nasal mucosa. About the clinical signs manifested, in the cases of involvement of the nasal structures, the main signs described in literature are bloody nasal secretion, sneezing, dyspnea and increased nasal plane volume, and are similar to those observed in the animals cited in this report. In the case of ocular cTVT, the increase volume with impairment and deformity of all ocular structures, as well as pain and pruritus corroborate with the clinical findings observed in the literature. The cytopathological test was the diagnostic tool used in all cases cited in this report and the cytopathological findings corroborates with those described in the literature. Vincristine sulfate is the drug of choice for the treatment of cTVT cases, and in the dogs of this report, this drug was successfully used leading to complete remission of lesions and clinical signs, as observed in other studies.
Keywords: nasal mucosa, ocular mucosa, venereal disease, round cells.
Amaral A.S., Gaspar L.F., Silva S.B. & Rocha N.S. 2004. Diagnóstico citológico do tumor venéreo transmissível na região de Botucatu, Brasil (estudo descritivo: 1994-2003). Revista Portuguesa de Ciências Veterinárias. 99(551):167-171.
Amaral A.V., Oliveira R.F., Silva A.P., Baylão M.L., Luz L.C. & Sant’ana F.J. 2012. Tumor Venéreo Transmissível Intra-ocular em cão: Relato de Caso. Revista Veterinária e Zootecnia. 19(1): 79-85.
Ferreira A.J., Jaggy A., Varejão A.P., Ferreira M.L., Correia J.M., Mulas J.M., Almeida O., Oliveira P. & Prada J. 2000. Brain and ocular metastases from a transmissible veneral tumour in a dog. Journal of Small Animal Practice. 41(4): 165-168.
Greatti W.F.P., Amaral A.S., Silva S.B., Gaspar L.F.J., Barbisan L.F. & Rocha N.S. 2004. Índices proliferativos do tumor venéreo canino transmissível pelas técnicas do CEC e KI-67 na citologia aspirativa com agulha fina. Archives of Veterinary Science. 9(1): 53-59.
Horta R.S., Viana A.A.S., Queiroz A.T., Lavalle G.E., Araújo M.R. & Araújo R.B. 2012. Diagnóstico diferencial entre sarcoma histiocítico e tumor venéreo transmissível com disseminação extragenital - relato de caso. Revista Clínica Veterinária. 17(1): 96-102.
Horta R.S., Fonseca L.S., Miranda D.F.H., Quessada A.M., Rocha Neto H.J. & Silva S.M.M.S. 2014. Tumor venéreo transmissível (TVT) com metástase para a glândula mamária. Acta Scientiae Veterinariae. 42(1): 1-6.
Huppes R.R., Silva C.G., Uscategui R.A.R., De Nardi A.B., Souza F.W., Tinucci Costa M., Amorim R.L., Pazzini J.M. & Faria J.L.M. 2014. Tumor Venéreo Transmissível (TVT): Estudo Retrospectivo de 144 casos. ARS Veterinária. 30(1): 13-18.
Lorimier L.P. & Fan T.M. 2007. Canine Transmissible Venereal Tumor. In: Withrow S.J. & Vail D.M. (Eds). Small Animal Clinical Oncology. 4th edn. Philadelphia: Elsevier, pp.799-804.
Marcos R., Santos M., Marrinha C. & Rocha E. 2006. Cutaneous transmissible venereal tumor without genital involvement in a prepubertal female dog. Veterinary Clinical Pathology. 35(1): 106-109.
Milo J. & Snead E. 2014. A case of ocular canine transmissible venereal tumor. The Canadian Veterinary Journal. 55(1): 1245-1249.
Park M., Kim Y., Kang M., Oh S., Cho D., Shin N. & Kim D. 2006. Disseminated transmissible venereal tumor in a dog. Journal of Veterinary Diagnostic Investigation. 18(1): 130-133.
Pereira J.S., Silva A.B., Martins A.L., Ferreira A.M. & Brooks D.E. 2000. Immunohistochemical characterization of intraocular metastasis of a canine transmissible venereal tumor. Veterinary Ophthalmology. 3(1): 43-47.
Rodrigues G.N., Alessi A.C. & Laus J.L. 2001. Tumor venéreo transmissível intra-ocular em cão. Ciência Rural. 31(1): 141-143.
Santos R.L. & Alessi A.C. 2016. Patologia Veterinária. 2.ed. Rio de Janeiro: Roca, 856p.
Tinucci-Costa M. 2009. Tumor venéreo transmissível canino. In: Daleck C.R., De Nardi A.B. & Rodaski S. (Eds). Oncologia em cães e gatos. São Paulo: Roca, pp.539-555.
Varaschin M.S., Woufers F., Bernins V.M.O., Soares T.M.P., Tokura V.N. & Dias M.P.L. 2001. Tumor venéreo transmissível canino na região de Alfenas, MG: formas de apresentação clínico patológicas. Revista Clínica Veterinária. 6(32): 332-338.
Woods J.P. 2013. Canine Transmissible Venereal Tumor. In: Withrow S.J., Vail D.M. & Page R.L. (Eds). Withrow & MacEwen´s Small Animal Clinical Oncology. 5th edn. St. Louis: Saunders, pp.692-696.
How to Cite
This journal provides open access to all of its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Such access is associated with increased readership and increased citation of an author's work. For more information on this approach, see the Public Knowledge Project and Directory of Open Access Journals.
We define open access journals as journals that use a funding model that does not charge readers or their institutions for access. From the BOAI definition of "open access" we take the right of users to "read, download, copy, distribute, print, search, or link to the full texts of these articles" as mandatory for a journal to be included in the directory.
La Red y Portal Iberoamericano de Revistas Científicas de Veterinaria de Libre Acceso reúne a las principales publicaciones científicas editadas en España, Portugal, Latino América y otros países del ámbito latino