Removal of a multilobular osteosarcoma in a 9 year old Labrador Retriever

A 9 year old, male castrated Labrador Retriever presented to Cornell University Veterinary School with a firm, fixed mass of the right zygomatic arch. Cytologic evaluation revealed this to be a mesenchymal neoplasm. Computed tomography studies were performed and showed the extensive local involvement of this mass with the calvarium. The owner opted for surgical removal of the mass. A dorso‐lateral approach was used to obtain best visualization of the lesion intra‐operatively. The mass, along with the right zygomatic arch, right eye and associated structures, caudal maxilla, and 2 molars were removed. The patient recovered uneventfully from surgery. Histopathology of the mass came back as a multilobular tumor of bone