Heart block, sudden death, and atrioventricular node mesothelioma

We report a case of mesothelioma of the atrioventricular node with congenital complete heart block and sudden death in a 15-year-old girl. This benign tumor probably represents a hamartoma derived from mesothelium with a constant anatomic location and uniform association with heart block. The clinical course of such patients, however, has been variable. The tumor has been associated with sudden, unexpected death in infancy or adolescence, but has more often been discovered as an incidental finding at autopsy in a middle-aged or elderly patient.