Labrador retriever with painful urination from penile cancer

Abstract

An approximately 8 yr old castrated male Labrador retriever presented for evaluation of weight loss, stranguria, and pollakiuria. Lysis of the proximal one-third of the os penis was diagnosed on abdominal radiographs, and a positive contrast urethrography revealed a smoothly marginated filling defect along the dorsal aspect of the urethra at the level of the radiographically observed osteolysis. Regional ultrasound revealed an echogenic mass at the proximal aspect of the os penis with a severely irregular and discontinuous periosteal surface. A penile hemangiosarcoma (HSA) was confirmed on histopathologic evaluation after a penile amputation and scrotal urethrostomy were performed. Although HSA is a common malignant neoplasm in dogs, lysis of the os penis has not previously been documented. Adjunctive chemotherapy, although recommended, was declined, and the patient survived 236 days postoperatively. That survival time is considerably longer than the average survival time for patients with HSA, other than cutaneous forms of HSA. Although an uncommon presentation, HSA of the penis should be considered a differential diagnosis in older canines with signs of lower urinary tract disease, especially in breeds that have been documented to be predisposed to HSA.