Cardiac tumors of adipocytes and cystic tumor of the atrioventricular node.

Lipomatous lesions of the heart and cystic tumor of the atrioventricular node are not common. A pathologist will only rarely encounter these entities, and in the case of the atrioventricular node tumor, only if they examine the conduction system. Most fatty lesions are not clinically significant; however, arrhythmias, blood flow obstruction, and valvular dysfunction may result from benign or malignant lipomatous tumors. Cystic tumor of the atrioventricular node has been implicated in the causation of sudden cardiac death, and there has been much academic interest concerning its cell of origin.