Primary and secondary bone tumours in the cat

ABSTRACT Both primary and secondary bone tumours are rare in cats. Of the twenty‐four cases of primary bone tumour, benign or malignant, in the cats of our study, the most common tumour was osteosarcoma (fifteen cats). The osteosarcomas tended to occur in aged female domestic short‐hair cats; nine of the fifteen originated in the long bones of the extremities and three involved the skull. Four juxtacortical osteosarcomas, three chondro‐sarcomas, and one example each of oesteoma and osteoid osteoma were found. The four juxtacortical osteosarcomas developed in relation to cranial bones, a location not recorded previously in cats. Of the five tumour‐like lesions of bone simulating primary tumours, three were aneurysmal bone cysts and two were fibrous dysplasias. Of the twenty‐nine cats with soft tissue tumours or tumour‐like lesions involving bone, eleven had fibrosarcoma, eight had squamous cell carcinoma, three had lymphosarcoma, two had rhabdomyosarcoma, and one example of each was malignant melanoma, haemangiosarcoma, reticulum‐cell sarcoma, meningioma and myositis ossificans. Osteoid osteoma, fibrous dysplasia and myositis ossificans were not previously recorded in the cat.