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

Abstract

Transmissible venereal tumour (TVT) is a sexually transmitted neoplasm that frequently affects dogs of either sex, in tropical and subtropical regions. TVT primarily involves the external genitalia, although extragenital sites have also been reported. This study describes the ocular manifestations of TVT in 25 naturally infected dogs and their response to treatment. Seventeen male and eight female dogs were included in the study. TVT ocular lesions were either unilateral (21 dogs) or bilateral (four dogs). Ocular lesions as the single manifestation of TVT were seen in 22 animals. One dog presented external genitalia involvement while two others were found to have tumours in the oral and nasal mucosa. Variably sized multilobular tumour masses with irregular surface were noticed on the bulbar conjunctiva of the nictitating membrane in 17 dogs, on the conjunctiva of the upper eyelid in five dogs and on the conjunctiva of the lower eyelid and adjacent skin in three dogs. Deep ulcerative keratitis was observed in eight animals. TVT diagnosis was based on cytology and histopathology. The large eye masses were surgically excised. All dogs were treated with a single chemotherapeutic agent (vincristine). After four weeks of treatment, complete remission of the tumours was evident in all but one animal. Extragenital primary ophthalmic TVT can be completely eliminated by vincristine chemotherapy, while any further ocular damage is prevented with the combination of the above treatment and surgical excision.

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

“…CTVT is transmitted when malignant cells are transferred directly from 1 dog to another dog via coitus, licking, biting or sniffing tumor areas, such as the external genitalia or skin . CTVT presents a low metastatic potential; however, metastases to the skin, lungs, abdominal organs, and central nervous system have been described . The biological behavior and pathogenesis of the primary extragenital forms of CTVT are still not well established because the number of cases is small in relevant reports .…”

Multifocal metastatic cutaneous and mucosal transmissible venereal tumour in a female puppy

“…Extragenital lesions are less commonly observed. When extragenital lesions involve the face or nasal passages, sneezing, epistasis, epiphora, halitosis, dental fistulae, tooth loss, exophthalmos, and facial or oral deformation with regional lymph node enlargement may be seen (Rogers and others 1998, Papazoglou and others 2001, Levy and others 2006, Mylonakis and others 2008, Koumnenou and others 2015). …”

“…The treatments that have proven the most effective for TVT are chemotherapy or radiation (Amber and others 1990, Rogers and others 1998). Surgical excision has variable reported success rates depending on location and extent of lesions, with an 18–60 per cent recurrence rate (Ganguly and others 2013, Awan and others 2014, Koumnenou and others 2015). Surgery and radiation were not pursued in this case due to extent of lesions, risk of recurrence following surgery and cost.…”

Conjunctival myxoma in a dog: clinical and histopathological features

“…Tumours involving the conjunctiva are considered uncommon in dogs, although a variety of case reports and case series have been published in veterinary literature, especially over the past 10 years …”

“…T umours involving the conjunctiva are considered uncommon in dogs, although a variety of case reports and case series have been published in veterinary literature, especially over the past 10 years. [1][2][3][4][5][6][7][8][9][10] Myxomas are rare tumours derived from primitive mesenchymal cells and are characterised by a large amount of mucin in the intercellular matrix. These benign, slow-growing neoplasms can occur at any site where there is connective tissue, but they more frequently affect joint tissue (synovial myxoma), 11 heart, 12 and teeth (odontogenic).…”