Cardiovascular recurrence of high-grade osteosarcoma presenting as atrial thrombosis and pulmonary embolism: A case report and review of the pediatric literature.

In the era of neoadjuvant and adjuvant chemotherapy, extrapulmonary involvement by high-grade osteosarcoma (HGOS) is rare. Importantly however, HGOS metastasis in the form of cardiovascular tumor thrombus portends a dismal prognosis. Thus, prompt and accurate identification of tumor thrombus is crucial. We report here two unique cases of recurrent HGOS, presenting as thrombotic events, in order to increase awareness and index of suspicion among practitioners regarding this presentation. Additionally, we review 14 previously reported pediatric cases of cardiovascular metastatic HGOS.