Mitral tendon prolapsing into the left ventricular outflow tract.

Intracardiac masses of the mitral valve are rare. Their differential diagnosis is wide, ranging from tumors (myxomas, lipomas and fibroelastomas), thrombi and abnormal muscular or fibrous bands. We report a case and management. A 68 year-old asymptomatic female who had undergone coronary angioplasty and stent placement in the left anterior descending artery for acute myocardial infarction four years earlier, was shown to have, on routine follow-up, an intracardiac mass originating from the anterior leaflet of the mitral valve and prolapsing into the left ventricular outflow tract (LVOT). The patient underwent surgical excision of the mass under cardiopulmonary bypass, to prevent cerebral or coronary embolization and sudden death due to the highly sensitive location of the mass, in the high-velocity flow LVOT. A transverse aortotomy provided exposure of the ventricular surface of the anterior mitral leaflet and revealed a fusiform mass attached to the medial segment of the anterior leaflet, resembling a secondary cordae, measuring 20 by 3 mm. The implantation was calcified on the ventricular aspect of the anterior mitral leaflet. This mass was completely excised. Postoperative recovery was uneventful. Peroperative and postoperative transesophageal echocardiography were normal. Histological examination showed a partially necrosed and calcified fibrous tissue lined by endothelium. The final diagnosis was that of a mitral tendon. Intracardiac masses of the mitral valve are rare lesions, mostly papillary fibroelastomas and myxomas and more rarely mitral tendons, which require surgical resection for prevention of embolization. The definitive diagnosis is often only obtained on histological analysis.