Osteogenic sarcoma of the femur in a mare

Abstract

A seven-year-old mare Was presented for evaluation of a left rear leg lameness and weight loss of five months duration. Physical exam revealed a non-weight bearing lameness of the affected leg with marked swelling of the stifle. Hematology and clinical chemistr ies were unremarkable. Radiographs revealed an invasive mass on the distal femfir. A bone biopsy was performed standing under local anesthesia and sedation. Osteosarcoma was diagnosed histologically using hematoxylin and eosin staining. Thoracic radiographs and nuclear scintigraphy were performed to access for metastatic disease. Radiographs were within normal limits. The scintigraphy showed several undef ined areas of increased uptake of the radionucleotide. A postmortem examination was performed. Osteosarcoma was confined to the distal femur evolving both condyles. Osteogenic sarcoma is a malignant bone tumor with proliferating spindle cell stroma producing osteoid or immature bone. ~ The incidence of osteosarcom a is relatively high in dogs, cats, and humans.l3 In man, osteosarcoma is one of the most commonly seen primary sarcomas of bony tissue. ~'4's Osteosarcoma occurs more frequently in dogs than cats, with the incidence of osteosarcoma about twice