Leiomyosarcoma of the canine urinary bladder, with metastases.

An enlarged nodular mass, assumed to be the prostate gland because of location and consistency, was palpated in the pelvic region of a 10-year-old German Shepherd Dog. Castration was performed as a therapeutic procedure after an estrogenic hormone failed to reduce the size of the mass. A tumor identified histologically as a seminoma was in the right testicle. The dog died 1 month after castration, and generalized metastatic neoplasia was observed at necropsy. The mass that involved the neck of the bladder and the metastases were identified as leiomyosarcoma.