CYSTIC PERIOSTEAL OSTEOSARCOMA IN THE TIBIA OF A DOG

Periosteal osteosarcoma, a rare neoplasm in dogs, was diagnosed in an eleven-year-old Golden Retriever. In this case, the tumour formed a si ngle, large, fluid filled cyst, that originated from the periosteum of the tibia. Periosteal osteosarcomas are intermediate grade tumours an d behave less aggressively than central osteosarcomas, however, they a re more malignant than the low grade parosteal osteosarcoma. Cure for periosteal osteosarcoma in people may be achieved in 70-80% of cases b y local excision. In this case euthanasia was elected one year post-am putation due to emaciation and lethargy associated with metastatic dis ease.