Primary Urinary Bladder Osteosarcoma in a Dog.

A 13-year-old, female Welsh corgi had a clinical history of haematuria and cystitis for 2-3 months. A 4 × 3 × 2 cm mass was excised surgically from the apex of the urinary bladder. A primary urinary bladder osteosarcoma was diagnosed histologically. Primary urinary bladder osteosarcoma is a rare tumour in man and animals. To the author's knowledge, there is no previously published report of a primary canine urinary bladder osteosarcoma.