Cutaneous Form of Transmissible Venereal Tumor (TVT) in a German Shepherd Dog: Case Report

Abstract

Canine Transmissible Venereal Tumor (CTVT), historically known as Sticker's sarcoma, represents a unique contagious round-cell neoplasm that primarily affects the external genitalia of dogs. While the genital form remains frequently encountered in routine veterinary practice, extragenital or purely cutaneous presentations are comparatively rare and often complicate the diagnostic process due to their atypical distribution. This case report documents an unusual manifestation of cutaneous TVT in a 4-year-old intact male German Shepherd dog. The patient presented with multiple ulcerated, nodular lesions prominently distributed on the muzzle, periocular region, dorsal trunk, and limbs, accompanied by concurrent bilateral corneal opacity. A definitive diagnosis was promptly achieved through Fine Needle Aspiration Cytology (FNAC), which revealed high cellularity comprising characteristic round cells containing distinct, pathognomonic cytoplasmic vacuoles. The underlying etiology was determined to be autoinoculation, resulting from the animal's licking behavior involving a previously healed genital tumor site. A targeted therapeutic course of Vincristine sulfate, administered intravenously at 0.025 mg/kg once weekly for four weeks, yielded a complete clinical cure, achieving total regression of all skin lesions alongside complete resolution of the ocular symptoms. This report underscores the critical necessity of including TVT in the differential diagnosis for nodular dermatological diseases and reaffirms the exceptional efficacy of vincristine chemotherapy for extragenital manifestations.