Association of ventricular noncompaction and histiocytoid cardiomyopathy: case report and review of the literature.

We report an association between ventricular noncompaction and histiocytoid cardiomyopathy. Both entities are rare, and only 2 cases of their association have been reported previously in the medical literature. Ventricular noncompaction is believed to be caused by an arrest of the normal endomyocardial development, resulting in a thin and compacted epicardial layer and a thickened noncompacted endocardial layer. Histiocytoid cardiomyopathy is a rare arrhythmogenic disorder characterized by aggregates of oncocytic cells involving predominantly the subendocardium. These cells are thought to be abnormal Purkinje cells. In our case, the histiocytoid cells showed strong cytoplasmic expression for the skeletal muscle transcription factor MyoD1, which could be attributed to cross reactivity with an undetermined cytoplasmic antigen.