Primary Bone Tumors in the Cat:

A description of the clinical behavior, radiographic signs, histologic appearance, therapy, and clinical sequelae in 15 cats with primary bone tumors seen over a 10‐year period is presented. Seven tumor types were identified: osteosarcoma (3 cats), chondrosarcoma (4 cats), parosteal osteosarcoma (2 cats), giant cell tumor (1 cat), ossifying fibroma (1 cat), solitary osteochondroma (1 cat), and osteochondromatosis (3 cats). The cats had a mean age of 8.4 years and there was no sex predilection. Domestic short‐hair, mixed‐breed cats comprised 80% of affected cats. A retrospective review of feline osteosarcomas was made and data was compared to that of canine osteosarcomas. Significant differences were the incidence of metastatic disease, the age on onset, forelimb‐hindlimb incidence, and duration of clinical signs. Five tumors were surgically excised successfully. Radiotherapy controlled one unresectable tumor. Three young adult cats had osteochondromatosis with progressively enlarging lesions limited to flat and irregular bones. Two of the three cats were FeLV positive. Metastatic disease was not detected in any cats in this study.