The Canine Transmissible Venereal Tumor: Etiology, Pathology, Diagnosis and Treatment

Introduction Transmissible venereal tumor (TVT), also known as infectious sarcoma, venereal granuloma, transmissible lymphosarcoma or Sticker tumor, is a benign reticuloendothelial tumor of the dog that mainly affects the external genitalia (Fig. 1 and Fig. 2) and occasionally the internal genitalia (Fig. 3a, Fig. 3b, and Fig. 3c). As it is usually transmitted during coitus [1] it mainly occurs in young, sexually mature animals [2]. TVT also affects wild canids [3]. Transmissible venereal tumor cells contain an abnormal number of chromosomes ranging from 57 to 64 and averaging 59, in contrast to the normal 78 of the species. Surface antigen characteristics suggest that all TVTs arose from a single original canine tumor [2]. The capacity of immunologic response of the host has a main role in the expansion of such tumors [4] with an increase in severity seen in immunologically compromised animals.