PRESENTATION : 8 year old FS Greyhound presented with left hindlimb lameness associated with a probable tumor in the left distal tibia.
HISTORY: The radiographic appearance of the lesion was consistent with a bony tumor and fungal serology was negative. A bone scan revealed a possible metastatic lesion in the right hindlimb, therefore amputation of the left hindlimb was not ideal.
PHYSICAL EXAMINATION: No abnormalities were noted apart from the left hindlimb lameness.
DIAGNOSIS: Possible metastatic appendicular osteosarcoma. Preoperative bloodwork was essentially normal. Thoracic radiographs were not indicative of pulmonary metastasis.
TREATMENT: Limb-sparing surgery was performed to remove the affected distal tibia en bloc and place a cortical bone allograft stabilized with a bone plate. Samarium therapy was performed 1 month postoperatively due to the possible metastatic bone lesion in the right distal tibia.
OUTCOME: Marked bone marrow suppression developed post-Samarium treatment therefore systemic chemotherapy with cisplatin was postponed until it resolved. Bony resorption of 50% of the cortical graft was evident on 10 week postoperative films. This did not resolve by 5 months postoperatively, therefore a cancellous bone graft was placed at the tibial non-union site. Pulmonary metastasis and hypertrophic pulmonary osteopathy developed 1 year postoperatively. The patient's life span from the time of surgery was 15 months.
DISCUSSION: The ideal candidates for limb-sparing surgery are patients with OSA of the distal radius that affects less than 50% of the bone.
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