Critical obstruction of the right ventricular outflow tract by a primary hemangioendothelioma in a seven month old.

A 7-month-old presented with failure to thrive and a murmur. Echocardiography demonstrated a large mass in the right ventricular outflow tract, extending through the pulmonary valve. During anaesthetic induction this caused critical obstruction of the outflow tract and cardiac arrest. Pathological diagnosis showed the lesion to be a primary hemangioendothelioma. Despite surgical excision and steroid therapy, the mass continued to grow for a period of 8 weeks, but then began to regress spontaneously.