Ocular manifestations of canine transmissible venereal tumour: a retrospective study of 25 cases in Greece

Effect of vincristine on intraocular pressure and tear fluid oxidative stress biomarkers in canine transmissible venereal tumor

BACKGROUND

The ocular side effects of cancer chemotherapeutic drugs are relatively uncommon. Nonetheless, the ocular system has a potentially high sensitivity to toxic substances. This study proposed a framework to assess the effect of vincristine chemotherapy on intraocular pressure, tear protein, and oxidative stress in canines with transmissible venereal tumor (TVT).

METHODS

The study group comprised 10 dogs with TVT, whose diagnosis was based on cytology, and all dogs were treated with vincristine for 4 weeks. Each animal was given a complete ophthalmic examination, followed by a standard Schirmer tear test. Before and 20 min after administering vincristine, intraocular pressure (IOP) was measured in the eyes with a noncontact tonometer. At any of the times mentioned, tear samples were collected using the Schirmer test procedure and were subjected to protein analysis-oxidative stress index (OSI), total antioxidant capacity (TAC), total oxidant status (TOS), nitric oxide (NO), and malondialdehyde (MDA) were determined, and standard statistical analysis was applied.

RESULTS

No significant differences were found in protein in tears, but mean Pre and Postinjection IOP revealed a significant decrease in the eyes each week. Also, results indicated significant differences in oxidative stress markers: increased OSI, NO, and MDA, and reduced TAC.

CONCLUSION

The importance of an increase in oxidative stress levels in the tears of vincristine-treated patients should be taken seriously, as it appears to play a role in the pathogenesis of eye disease. Therefore, during the treatment weeks prior to prescribing vincristine, eye diseases should be evaluated and considered.

Blepharitis and Neoplasms of the Canine Eyelid Margin and Skin

Canine eyelid masses (tumors) should include the differential clinical diagnoses of neoplasia and blepharitis. They have many common clinical signs including tumor, alopecia, and hyperemia. Biopsy and histologic examination remains the most effective diagnostic test to establish a confirmed diagnosis and appropriate treatment. Neoplasms are typically benign (tarsal gland adenomas, melanocytomas, and so forth) with the exception of lymphosarcoma. Blepharitis is noted in 2 age groups including dogs aged less than 1.5 years and middle aged to older dogs. Most blepharitis cases will respond to specific therapy once an accurate diagnosis is established.

Sex disparity in oronasal presentations of canine transmissible venereal tumour

BACKGROUND

The canine transmissible venereal tumour (CTVT) is a contagious cancer spread by the direct transfer of living cancer cells. CTVT usually spreads during mating, manifesting as genital tumours. However, oronasal CTVT is also occasionally observed, and presumably arises through oronasal contact with genital CTVT tumours during sniffing and licking.

METHODS

Given that sniffing and licking transmission behaviours may differ between sexes, we investigated whether oronasal CTVT shows sex disparity.

RESULTS

Twenty-seven of 32 (84%) primary oronasal tumours in a CTVT tumour database occurred in males. In addition, 53 of 65 (82%) primary oronasal CTVT tumours reported in the published literature involved male hosts. These findings suggest that male dogs are at four to five times greater risk of developing primary oronasal CTVT than females. This disparity may be due to sex differences in licking and sniffing activity, perhaps also influenced by sex differences in CTVT accessibility for these behaviours.

CONCLUSION

Although oronasal CTVT is rare, it should be considered as a possible diagnosis for oronasal tumours, particularly in male dogs.

Rhinoscopic Appearance and Clinical Features of a Nasal Transmissible Venereal Tumor in a Dog

A 2-year-old male neutered mixed breed dog was referred for evaluation of left-sided unilateral epistaxis and mucoid discharge following adoption from Mexico 2 months prior to presentation. Computed tomography (CT) showed soft tissue that filled the entirety of the left nasal passage with mild turbinate loss. Subsequent rhinoscopy revealed multifocal patches of discrete, white, wispy, vascularized abnormal tissue in the left nasal cavity. Cytology and histopathology procured with rhinoscopic-guidance were suspicious for transmissible venereal tumor (TVT). Confirmation of a TVT diagnosis was made with polymerase chain reaction for the long interspersed element inserted upstream of the c-myc gene. The dog was treated with 4 cycles of vincristine (0.5 mg/m², IV, once every 7 days) with complete and sustained resolution of clinical signs shortly after the third cycle. Nasal TVT in dogs is an uncommon presentation of a neoplasm that primarily results in genital or oral lesions. There is a void in the veterinary literature regarding the rhinoscopic appearance, as well as limited clinical descriptions of nasal TVT. Therefore, the objectives of this report were to provide a detailed description of the rhinoscopic appearance of a canine nasal TVT, in addition to clinical features, diagnostic findings, CT imaging, and successful therapeutic management.

Neoplasmas cutâneos em cães: 656 casos (2007-2014) em Cuiabá, MT

RESUMO: Os neoplasmas cutâneos em cães apresentam elevada e relevante prevalência em todo o Brasil. Sendo assim, objetivou-se determinar a frequência e algumas características epidemiológicas dos neoplasmas cutâneos em cães diagnosticados no Laboratório de Patologia da Universidade Federal de Mato Grosso (LPV-UFMT), Cuiabá, entre os anos de 2007 a 2014. Foram revisados os protocolos de necropsias e biopsias do LPV-UFMT, de cães com neoplasmas cutâneos. Dados referentes à idade, sexo, raça dos cães afetados, localização anatômica, tamanho, diagnóstico histomorfológico e comportamento biológico foram coletados e analisados através de uma análise estatística descritiva. Adicionalmente o teste χ2, foi utilizado para associações entre comportamento biológico e tamanho da massa. Dos 3566 exames realizados, 656 (18,4%) foram diagnosticados como tumores cutâneos sendo cães adultos e idosos das raças Pit Bull, Boxer e Poodle os mais acometidos. Dentre os 11 padrões morfológicos mais diagnosticados o mastocitoma, carcinoma de células escamosas (CCE) e os tumores de origem vascular foram os mais frequentemente relatados. Em relação ao sítio anatômico, a cabeça foi a mais acometida. A maioria dos tumores benignos apresentaram menos de 1cm de diâmetro e os malignos de 3 a 5cm. O aumento de neoplasmas em adultos e idosos pode estar relacionado ao somatório de danos causados por agentes carcinogênicos e o comprometimento imunológico.

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.