Sudden death in right ventricular dysplasia with minimal gross abnormalities.

Arrhythmogenic right ventricular cardiomyopathy is emerging as a relatively common cause of exercise-induced sudden death in the young. The diagnostic criteria at autopsy are, however, not fully established, leading to both over- and underdiagnosis. We report a young man and a young woman dying suddenly of right ventricular dysplasia during exercise, in whom the gross autopsy findings in the right ventricle were minimal or even absent. However, the histologic features in both right and left ventricles were typical of the disease, and consisted of fibrofatty infiltrates with typical myocyte degeneration of the right ventricle and subepicardial regions of the left ventricle. These cases illustrate that microscopic findings are diagnostic and may be present in the absence of gross findings. Marked fat replacement is not essential for the diagnosis of right ventricular dysplasia, and the right ventricle should be extensively sampled histologically in all cases of sudden unexpected death, especially those that are exercise related.