Two unusual cases of metastatic osteosarcoma detected by Tc-99m MDP bone scintigraphy

Tc-99m MDP bone scintigraphy is widely used for initial staging and subsequent follow-up of patients with osteosarcoma. Two unusual cases are presented here, one with diffuse pleural metastases and one with diffuse peritoneal metastases. In one case, an abnormal bone scan was the first indication of metastatic disease. Both the metastatic pattern of osteosarcoma and the indications for bone scintigraphy are reviewed.