Padrões morfológicos e critérios de malignidade do tumor venéreo transmissível aos exames citopatológico e histopatológico

Vincristine and ivermectin combination chemotherapy in dogs with natural transmissible venereal tumor of different cyto-morphological patterns: A prospective outcome evaluation

Vincristine is the first-line drug for the chemotherapy of canine transmissible venereal tumor (CTVT). Drug resistance is related to tumor cyto-morphological patterns of CTVT. There are anti-cancer properties of ivermectin, thus, a combination of ivermectin and vincristine could be an effective chemo-therapeutic treatment regimen for CTVT. Study aims, therefore, were to (1) assess the frequency of CTVT cyto-morphologies, and (2) evaluate treatment efficacy and possible adverse reactions to vincristine compared with a combination vincristine and ivermectin. Dogs (n = 41) with CTVT were characterized by tumor cyto-morphology and disease severity and of those, 20 were randomly allocated into two groups. There was a control group (G-Vin; n = 10) in which there was treatment with vincristine; and an experimental group (G-Iv/Vin; n = 10) in which there was treatment with the ivermectin/vincristine combination. Although dogs in the G-Iv/Vin group had more severe disease at the beginning of the study (P = 0.0031), the number of weeks and chemotherapy sessions until tumor remission were similar among dogs of the two groups, indicating both treatments were effective. There was a decrease in the leukocyte counts (P = 0.0020), related to neutropenia (P = 0.0371) in the G-Vin but not the G-Iv/Vin treatment group. There was no tumor resistance that developed during the study regardless of the treatment regimen used or tumor cytomorphology. In summary, the use of the vincristine/ivermectin combination was well tolerated and efficacious for CTVT treatment.

Tumor venéreo transmissível canino com resistência quimioterápica e metástase esplênica - Relato de caso

O Tumor Venéreo Transmissível Canino (TVTC) é uma neoplasia de células redondas que tem a particularidade de se implantar em mucosas que tenham perdido a sua integridade. Nesse local o tumor prolifera e ocasionalmente origina metástase. Em geral, o tumor responde ao tratamento com sulfato de vincristina, porém a resistência quimioterápica associada ao fenótipo tumoral tem sido documentada. Objetivou-se relatar um caso de TVTC genital de fenótipo citológico misto com metástase esplênica e o insucesso da quimioterapia com sulfato de vincristina, em uma fêmea canina, da raça Australian Cattle Dog, de cinco anos de idade. Após diagnóstico citológico e histológico, o tumor primário foi ainda caracterizado em fase de progressão e mostrou baixa expressão de moléculas do complexo principal de histocompatibilidade MHC (4,4 ± 2% classe I e 11 ± 4,1% classe II). A cadela foi submetida à ovariohisterectomia e esplenectomia terapêutica e não apresentou recidiva do tumor após 12 meses de acompanhamento clínico.

Computer tomographic imaging in 4 dogs with primary nasal canine transmissible venereal tumor and differing cellular phenotype

Primary nasal canine transmissible venereal tumor (CTVT) without genital affection is uncommon. The aim of this report was to describe the primary nasal CTVT findings and CT staging in 4 dogs with different cytological phenotypes. Three male dogs and 1 bitch were evaluated for their chronic histories of sneezing, snoring, mucopurulent nasal discharge and nasal deformation. Cytological examination of nasal secretions suggested CTVT, confirmed by histopathological examination and LINE‐1/c‐myc. Males had the plasmacytoid phenotype of CTVT, and the bitch had the lymphocytoid phenotype. CTVT were staged based on the CT findings using modified Adams staging system. The bitch was classified as stage 1, 2 males were classified as stage 3 and 1 male as stage 4. All dogs had a complete tumoral remission after chemotherapy. Plasmacytoid phenotype was identified in cases with most important damage of the nasal cavity. However, the cytological type did not affect the response to chemotherapy.