Mesothelioma of the Atrioventricular Node

In a 17-year-old girl with first degree heart block and two ventricular septal defects, a mesothelioma of the atrioventricular node was noted upon histologic examination of the conduction system. Predominant in the female sex, the condition may occur at any age, 16 of the reported cases being under 30 years of age. The tumor may either be sufficiently large as to be evident grossly or may be discovered only upon histologic examination. Heart block with complication of Stokes-Adams attacks and sudden death is common.