Role of exfoliative cytology in the diagnosis of canine transmissible venereal tumour

The objectives of this study were to evaluate the role of exfoliative cytology in the diagnosis of canine transmissible venereal tumour and to improve the success rate of surgical excision of this tumour. The technique was used to screen 360 dogs and, at the time of surgery, 34 clinical cases. Seventy-five per cent of the cases detected by screening were described as early stage disease in comparison with 23 per cent of cases reported by owners. The value of exfoliative cytology at the time of surgery to determine tumour cell removal was demonstrated by the reduction in local tumour recurrence from 22 per cent to 8 per cent. The technique is, therefore, recommended for use in screening dogs for canine transmissible venereal tumour and in determining the extent of surgical removal. However, more work is needed to assess its applicability in practice by determining its sensitivity, specificity and predictive values of a positive and negative test answer.     

Canine transmissible venereal tumour and ovarian papillary cystadeno-carcinoma in a bitch

A young German shepherd dog was presented for a protruding vaginal mass of one month's duration. Clinical appearance of the mass was suggestive of a canine transmissible venereal tumour. Diagnosis was confirmed by cytology; a single drug chemotherapy regimen using vincristine was instituted. Regression was evident within seven days after the first treatment. Bilateral ovarian papillary cystadenocarcinoma was an incidental finding after an elective ovariohysterectomy was performed.     

Metastatic transmissible venereal tumour in dogs

This report presents six cases of canine transmissible venereal tumour (TVT) in the genital organs with metastasis to extragenital locations. These extragenital sites were the skin, lymph nodes, spleen, tonsils, liver and lung. Foci of metastasis were found in six different organs in one case, two organs in another case and one organ in the remaining four cases. Multiple tumour nodules were, however, found in certain organs such as the skin and spleen. The extragenital tumours were identified as TVT on the basis of their histological similarity to the primary genital tumours. Metastasis appeared to be mainly by lymphatic pathways and by oral implantation. Résumé. Ce rapport présente six cas de tumeur vénérienne transmissible (TVT) dans les organes génitaux avec métastase aux endroits extragénitaux. Ces endroits extragénitaux étaient la peau, les nouds lymphatiques, la rate, les amygdales, le foie et les poumons. Des foyers de métastase ont été trouvés dans six organes différents dans un cas, dans deux organes dans un autre cas et dans un organe dans les quatre cas restant. On a, cependant, trouvé des tumeurs multi-nodulaires dans certains organes tels que la peau et la rate. Les tumeurs extragénitales ont été identifiées comme TVT en se basant sur leur similarité histologique aux tumeurs génitales primaires. La métastase semblait ětre principalement par voies lymphatiques et par implantation orale. Zusammenfassung. Dieser Bericht stellt sechs Fǎlle dar von ùbertragbar venerischem Hunde-Tumor (TVT) in den Geschlechtsorganen mit Métastase an extragenitalen Stellen. Dièse extragenitalen Stellen waren die Haut, Lymphknoten, Milz, Mandeln, Leber und Lunge. Herden von Metastasen fand man in sechs verschiedenen Organen in einem Fall, zwei Organen in einem anderen Fall und in einem Organ in den ùbrigen vier Fǎllen. Zahlreiche Tumorknǒtchen (Noduli) wurden jedoch in gewissen Organen wie Haut und Milz gefunden. Die extragenitalen Tumoren waren als TVT identifiziert auf Grund ihrer histologischen ǎhnlichkeit mit den primaren Geschlechtstumoren. Metastasen traten hauptsàchlich durch lymphatische Bahnen und durch orale Einpflanzung ein.     

Evaluation of a genetic assay for canine transmissible venereal tumour diagnosis in Brazil

The canine transmissible venereal tumour (CTVT) is a transmissible cancer that is spread between dogs by the allogeneic transfer of living cancer cells. The infectious agents in CTVT are the living cancer cells themselves, which are transmitted between dogs during coitus. CTVT first arose several thousand years ago and the disease has a global distribution and is frequently observed in dogs from Brazil. We evaluated the utility of a LINE‐MYC quantitative polymerase chain reaction for diagnosis of CTVT cases in Brazil. Our analysis indicated that the LINE‐MYC rearrangement was detectable in all CTVT samples but not in their corresponding hosts. This genetic assay proves to be a useful tool for providing a definitive molecular diagnosis of CTVT, which presents with varying degrees of aggressiveness and invasiveness in different host dogs and can therefore be a diagnostic challenge in some specific cases.     

Metastasis of a transmissible venereal tumour to the pituitary

This report presents a case of metastasising transmissible venereal tumour (TVT) with lesions of the penis, lip, spleen and pituitary. The clinical picture is outlined and the associated diagnostic radiographic procedures used to reach a final diagnosis of a space–occupying lesion in the region of the pituitary are described. A definitive diagnosis of a metastasizing TVT was reached by histopathological examination and it is concluded that the pituitary and spleen metastases are examples of the systemic dissemination of the original penile tumour whilst the lip lesion probably arose by direct contact.     

Clinicopathological study of canine transmissible venereal tumour in leishmaniotic dogs

Introduction : Canine transmissible venereal tumour is occasionally observed in leishmaniotic dogs, and Leishmania amastigotes can be harboured in canine transmissible venereal tumour cells. Objectives : The aim of this paper was to investigate the clinicopathological significance of the association of both diseases. Methods : Nineteen dogs affected by canine transmissible venereal tumour and canine leishmaniasis were studied retrospectively. Results : In these dogs, the tumour manifested a large size and often aggressive behaviour (42%) and no predictive sign of spontaneous regression was observed. Sporadic Leishmania amastigotes were found within the canine transmissible venereal tumour in three cases, probably transported by infected macrophages often infiltrating the tumour. A high Leishmania parasitisation of canine transmissible venereal tumour was observed in two other cases and verified by immunohistochemistry. Clinical Significance : Canine transmissible venereal tumour is a tumour of the dog able to harbour a large number of Leishmania parasites. Alternatively, the systemic disease (canine leishmaniasis) may lower the immune defence against malignancy (canine transmissible venereal tumour).     

Mitosis and apoptosis in canine cutaneous histiocytoma and transmissible venereal tumour

Cell proliferation and apoptosis in canine cutaneous histiocytomas and transmissible venereal tumours were examined in twenty cases. The Ki-67 immunohistochemistry and Tunel methods were used to detect mitotic activity and apoptosis, respectively. The number of Ki-67 immunoreactive cells was 11.65 (+/- 1.1706) in canine cutaneous histiocytomas and 17 (+/- 2.1751) in transmissible venereal tumours. The mean values of apoptotic cells for canine cutaneous histiocytomas and transmissible venereal tumours were 13.25 (+/- 1.8758) and 8.52 (+/- 1.1007), respectively. It was considered that mitotic activity and apoptotic indices were useful in differentiation of canine cutaneous histiocytomas and transmissible venereal tumours. The correlation values for canine cutaneous histiocytomas and transmissible venereal tumours were 0.359 (+/- 0.330) and -0.232 (+/- 0.344), respectively. No significant (P > 0.05) correlation was found between mitosis and apoptosis in these two tumour types.     

Brain and ocular metastases from a transmissible venereal tumour in a dog

A five-year-old crossbred dog was referred with rapidly growing masses over its penis and right popliteal lymph node. The dog had severe blepharospasm, congestion of episcleral vessels and rubeosis iridis of the left eye. A presumptive diagnosis of transmissible venereal tumour (TVT) and iridocyclitis was made based on the results of fine needle aspiration. Chemotherapy with vincristine and prednisolone was initiated and after four months the dog made a complete recovery. However, the dog subsequently relapsed, showing miosis, blepharospasm and a well defined mass within the anterior chamber of the left eye. In addition, the dog exhibited generalised 'grand mal' type seizures. Computed tomographic (CT) examination of the brain revealed two distinct masses in the left frontal lobe. Because of the poor prognosis, the owners elected to have the dog euthanased. On histopathology, metastases of TVT in the left eye and left cerebral hemisphere were found, showing no specific staining for CD3, immunoglobulin (Ig) G, IgM and lambda light chains. It was therefore concluded that the tumour growth was progressive, and that there was an absence of local humoral immune response against TVT in this case.     

The chromosomes of the transmissible venereal tumour of dogs in Ibadan, Nigeria

Cytogenetic studies on 11 transmissible venereal tumours in seven dogs in Ibadan, Nigeria, are reported. The number and the morphology of the chromosomes, as shown by the metaphase cells, revealed that the tumour cells have similar cytogenetic features to those reported in other parts of the world. The suggestion of common sources of infection for the animals in the different geographical locations of the world was supported.     

Use of a murine xenograft model for canine transmissible venereal tumor

OBJECTIVE: To develop a murine model for canine transmissible venereal tumor (CTVT). ANIMALS: Thirty-three 6-week-old NOD/LtSz-scid (NOD/SCID) mice and seven 6-week-old C57BL/6J mice. PROCEDURE: Samples of CTVT were excised from a 3-year-old dog and inoculated SC into ten 6-week-old NOD/SCID mice to induce growth of xenograft transmissible venereal tumor (XTVT). To establish mouse-to-mouse transmission, samples of XTVT were removed and inoculated SC into 4 groups of 6-week-old NOD/SCID mice and into a control group. Samples of CTVT were also inoculated into immunocompetent C57BL/6J mice for a mouse antibody production (MAP) test. The canine and xenografted tumors were evaluated cytologically and histologically, and polymerase chain reaction was performed for detection of the rearranged LINE/c-MYC junction. RESULTS: 8 of 10 NOD/SCID mice that were inoculated with CTVT developed tumors 3 to 10 weeks after inoculation. In the second-generation xenograft, all mice developed tumors by postinoculation day 47; 1 X 10(6) of XTVT cells were enough to create a xenograft. Metastases developed in 4 of 20 mice. Xenografted and metastatic tumors retained cytologic, histologic, and molecular characteristics of CTVT. Results of the MAP test were negative for all pathogens. CONCLUSION: We established an NOD/SCID murine model for XTVT and metastasis of CTVT. This model should facilitate study of tumor transplantation, progression, and metastasis and should decrease or eliminate the need for maintaining allogenic transfer in dogs.     

Urinary tract infection: The role of canine transmissible venereal tumour

The role of transmissible venereal tumours in the pathogenesis of urinary tract infection in dogs was investigated in 86 dogs. Fifty-five had transmissible venereal tumours, and the remaining 31 animals were used as controls. A thorough clinical examination of the external genitalia was carried out in each case. In the dogs with transmissible venereal tumours, the sites of attachment were recorded. Urine samples were taken by cystocentesis and the external genitalia swabbed; the samples were cultured for bacteria using standard methods. Tumours were found on the prepuce and other parts of the penis in male dogs; in bitches they were found in the vagina, vestibule or the vestibulovaginal junction. Dogs with transmissible venereal tumours were found to be at a high risk of having bacteriuria (odds ratio [OR] = 7.04). Obliteration of the urethral orifice by the tumour, possibly leading to urine retention, was thought to be the main reason for the high incidence of urinary tract infection among dogs with transmissible venereal tumours. Long-standing cases of transmissible venereal neoplasia had a higher chance of becoming bac-teriuric compared with recent cases (OR=29–60). This study indicates that transmissible venereal tumour may be a predisposing factor for the development of urinary tract infection.     

A Clinico-pathological study on the effect of vincristine on transmissible venereal tumour in dogs

Transmissible venereal tumour (TVT) is a coitally transmitted neoplasm of dogs and is common among sexually active dogs, where sexual behaviour is not under control. Several treatment options are available for the treatment of the tumour, with chemotherapy being the most commonly employed. In this study, we investigated the clinical and cytological changes after weekly vincristine sulphate administration in 38 cases of naturally occurring TVT. Tumours totally regressed in 31 dogs after two to seven doses (mean 3.54 +/- 1.01) of vincristine. One dog died after the fifth dose of vincristine, and in six dogs, an additional treatment with doxorubicin was needed. Masses were still present in four dogs and the histopathological examination revealed small nodules of granulation tissue in two dogs, while viable tumour cells were identified in the remaining two cases. No recurrences were observed in a follow-up period of 7-49 months (mean 13.64 +/- 9.66); in one dog, granulation tissue was detected in the surgery site after 2 months. Treatment success could easily be followed by the cytological changes. In conclusion, vincristine was found to be effective chemotherapeutic agent.     

A retrospective evaluation of four surgical methods of treating canine transmissible venereal tumour

A total of 109 lesions were treated in a total of 109 dogs and bitches using simple surgical excision or diathermy, with or without the simultaneous removal of the gonads. Evaluation of the case, 49 months after surgery, showed that 35 (32.1 per cent) of the tumours had regressed completely whilst 74 (67.9 per cent) had recurred. Excision using diathermy was the more effective treatment irrespective of whether the gonads were removed. There was a significant difference in the frequency of recurrence and the time interval for it to recur (P < 0.05 and P < 0.25 respectively) when the methods of treatment were compared, however castration of either males or females had no significant effect upon the frequency of recurrence.     

Primary intranasal transmissible venereal tumour in the dog: a retrospective study of six spontaneous cases

The medical records of six dogs with primary intranasal transmissible venereal tumour (TVT) were reviewed. Epistaxis (4/6), serosangineous nasal discharge (2/6), oronasal fistulae (2/6), facial swelling (1/6) and submandibular lymphadenopathy (3/6) due to reactive hyperplasia (2/3) and metastasis (1/3) were the most common complaints and clinical findings. Diagnosis was made by rhinoscopy and confirmed by cytology and histopathology in five dogs and by cytology only in one dog. The microscopic appearance of the tumours with both diagnostic techniques was typical of TVT. Four cases were treated effectively with four to five weekly cycles of vincristine monotherapy that resulted in complete resolution of TVT masses in approximately 1 month. One case was resistant to this kind of treatment and another one was lost to follow-up.     

Extragenital transmissible venereal tumour associated with circulating neoplastic cells in an immunologically compromised dog

An adult male intact boxer was presented because of diffuse cutaneous nodules. Fine‐needle aspirate revealed transmissible venereal tumour (TVT) cells. Neoplastic cells were also observed in the peripheral blood. Associated simultaneous diseases included leishmaniosis, demodicosis, papillomatosis and coccidiosis. Immunosuppression may have aggravated disease and triggered widespread metastases. The dog was hospitalized and administered oral amoxicillin/clavulanate, subcutaneous meglumine antimonite to treat leishmaniosis and oral chlortetracycline to treat coccidiosis. Intravenous injection of vincristine at weekly interval was used to treat TVT. A rapid regression of cutaneous nodules was noted; however, intractable diarrhoea developed, eventually leading to death after 18 days. This is the first report describing an unusual case of extragenital TVT associated with circulating neoplastic cells in an immunosuppressed dog presenting with multiple cutaneous nodules.     

Effects of vincristine treatment on semen quality in a dog with a transmissible venereal tumour

The effect of vincristine treatment on semen parameters in a male boxer with a genital transmissible venereal tumour are described. The dog was treated with vincristine intravenously at 0.5 to 0.7 mg/m2 body surface area per week for six weeks until complete regression of the tumour occurred. Semen samples were collected before each application and then at weeks 10, 12, 17, 21 and 23 after the start of therapy. There were no alterations in libido or in testicular size and consistency either during or after treatment. Total sperm count decreased to abnormally low values during weeks 4 and 5, and then began to increase up to pretreatment values. No significant alterations in the other semen parameters were found during the study period.