Obstructive accessory mitral valve tissue in an adult patient: a case report

Accessory mitral valve tissue is a rare congenital anomaly that is commonly diagnosed in early childhood and rarely in adulthood. It is usually asymptomatic. However, it may cause left ventricular outflow tract obstruction in a way that mimics various other causes of obstruction. A 72-year-old Caucasian man complained of chest discomfort and exertional dyspnea for 3 months. There were no specific findings from a physical examination except systolic murmur. Transthoracic echocardiography demonstrated a mass on the mitral valve extending to the intraventricular septal, raising the pressure gradient flow across the aortic valve. Transesophageal echocardiography showed parachute-like tissue connected to the anterior leaflet of the mitral valve causing left ventricular outflow tract obstruction. During the surgery preparation period, he underwent coronary angiography and computed tomography to study the anatomy surrounding the mass. After surgery, biopsy showed non-specific findings.

When facing a case of aortic valve stenosis, accessory mitral valve tissue should be kept in mind as one of the possible underlying causes despite its rarity. Although it is simple and noninvasive, echocardiography remains the best diagnostic procedure to make the correct decision about management and to define the golden time for surgical intervention.