Morphoathological Description of an Extra Genital Canine Transmissible Venereal Tumor

The transmissible venereal tumor (TVT) is a contagious and sexually transmissible neoplasia of unknown origin. In natural conditions the tumor mainly affects the external genitalia of both male and female dogs. A 6- year old male German shepherd dog, weighing 16 kg was presented for evaluation of a mass on the nasal cavity which the owner had noticed 2 months ago. Clinical examination revealed multiple nodular ulcerated lesions of varying sizes from 1 to 3 cm in diameter over the nasal cavity. The tumor mass had a firm consistency, was hyperemic and ulcerated. Histopathological examination showed uniform-sized dense cells arranged in solid sheets and clusters interlaced by a little connective-tissue stroma. The cells were round and ovoid, with a moderate amount of cytoplasm that was either clear or finely granular and had a large nuclear/ cytoplasmic ratio. On the basis of the clinicopathological findings, this mass was diagnosed as a transmissible venereal tumor.