Metastatic osteosarcoma presenting as a single pulmonary microembolus.

There are only a few published reports of tumor emboli from osteosarcoma. We are reporting a 17-year-old adolescent boy with a history of localized osteosarcoma who developed a symptomatic pulmonary artery tumor embolus. He was initially diagnosed with a pulmonary thromboembolism. This is the first reported case of a single tumor embolus developing after surgical resection of a tumor with 100% necrosis after chemotherapy and no evidence of metastatic disease at the time of surgery. Pulmonary tumor embolism should be considered in the differential diagnosis in patients with cancer who present with dyspnea. The differentiation of tumor embolus from other causes of dyspnea is important for treatment plan.