Low-grade myofibroblastic sarcoma of the heart causing sudden death

A 5-year-old Asian girl collapsed at school and was dead on arrival to the hospital. At autopsy, she had a tumor arising from her aortic valve. Histology revealed a low-grade myofibroblastic sarcoma, which we believe occluded a coronary artery ostium, leading to sudden death. Primary cardiac neoplasms are rare. The most common primary cardiac neoplasm is the cardiac myxoma. Although uncommon, the most prevalent primary malignant tumors of the heart are sarcomas, and regardless of the subtype, the prognosis is typically poor. We present a case of a primary cardiac sarcoma presenting as sudden death in a 5-year-old Asian girl. Pathologic examination of the lesion confirmed that this was an atypical myofibroblastic neoplasm, consistent with a low-grade sarcoma. Pediatric cardiac sarcomas are rare in general, and this is the first reported case of a valvular low-grade myofibroblastic sarcoma presenting in a child.