Osteosarcoma in a cow

Abstract

A mass involving the maxilla of a cow was determined to be an osteosarcoma. Microscopically, the mass was composed of plump pyriform cells aligned along thin trabeculae of osteoid. Osteosarcoma rarely develops in large animal species, but when it does, it is usually found in the skull and must be differentiated from more common diseases, such as actinomycosis and tooth abscesses.