Cardiac rhabdomyoma.

Primary tumors of the heart are exceedingly rare with a prevalence rate of around 0.01% in autopsy studies. A majority of primary cardiac tumors are benign. Rhabdomyomas are the most common of benign pediatric cardiac tumors. A newborn female infant presented with perioral cyanosis and respiratory distress. She deteriorated progressively. The infant expired, and at autopsy, dissection of the heart revealed a large tumor mass in the interventricular septum. Histologically, the mass showed the classic "spider cells," and a diagnosis of cardiac rhabdomyoma of childhood was established.