Primitive Multipotential Primary Sarcoma of Bone in a Cat

Tumors of bone usually are categorized by the differentiation of most neoplastic cells. Most bone tumors have as their basic components. chondroid. osteoid or fibrous connective tissue and are classified as chondrosarcoma. osteosarcoma and fibrosarcoma IS]. Diagnosis is difficult when a bone tumor has more than one area of differentiation. Tumors with areas of chondroid and osseous differentiation have been reported as a primitive multipotential sarcoma of bone in man 14, 51. We report such a tumor in a cat. A biopsy of a facial tumor from a 3’iz-year-old female domestic short hair cat submitted to the C. E. Kord Animal Disease Laboratory for histological evaluation. The tissue was diagnoscd as a mesenchymal chondrosarcoma. Three months later the cat’s tumor was enlarged and the cat had purulent nasal discharge, loss of maxillary tooth on the side with the tumor. depressed appetite and weight loss. The swelling did not seem painful. The cat was killed and necropsied. The only lesion seen at postmortem examination was a mass that replaced the left naris and sinuses and invaded the orbit. The nasal septum was displaced but there was no invasion of the right sinuses and nasal passages. The tumor was dense. white and glistening, and had areas of hemorrhage and necrosis. No calcification was noted.