Transitional cell carcinoma in the distal urethra of a female Golden retriever

ABSTRACT

Background: Urinary tract tumours represent only 0.5-1% of neoplasms in dogs, and transitional cell carcinoma (TCC) is the most common. It is most common to find TCCs in the trigone region. Diagnosis can be made with image analysis, cytology or histology. With non-infiltrative lesions in the early stages, it is possible to obtain a biopsy by endoscopy. Surgical resection is the treatment option of choice for this tumour. Dogs with poor response to chemotherapy or at an advanced stage of the disease are candidates for palliative treatment. This paper reports an special case of TCC located in the distal urethra of a female dog, obtaining the diagnosis through endoscopy, cytology and immunohistochemistry.Case A nine-year old, female, neutered Golden Retriever was referred for examination after suffering vaginal bleeding. Vaginal palpation revealed an apparent mass on the vaginal floor. Cytology by imprinting the mass revealed a carcinoma. A vaginoscopy was performed on the patient. An endoscopic examination showed normal vaginal mucosa, but, through the urethra, a mass was observed in the urethral lumen, with thickening and dilatation of the urinary meatus. A tissue biopsy was obtained. Episiotomy was performed to remove the tumour. Histopathological studies diagnosed the mass as transitional cell carcinoma with incomplete surgical margins. An immunohistochemistry analysis of the...