Case report:
The patient was a 19 years old woman who referred to advanced echocardiography lab due to a history of heart murmur and a mass attached to anterior mitral leaflet at previous transthoracic echocardiography. Patient didn’t have fever, anorexia, weakness, and peripheral stigmata of infective endocarditis or history of emboli. After first echocardiography, patient had been evaluated for infective endocarditis and non-bacterial thrombotic endocarditis (NBTE). All laboratory findings including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complete blood count (CBC), blood cultures, renal function tests, and screening test for Systemic lupus erythematosus were normal. Ultrasonography of abdomen and pelvic were normal. She underwent transthoracic and transesophageal echocardiography at our center which showed a large mobile oval shape accessory mitral valve, measured about 18 mm that attached to ventricular surface of the anterior mitral leaflet (Movie clips 1,2). AMV was echogenic, with echo-free central part (cyst-like) and sharp borders which resembles the mitral valve (Figures 1,2). LVOT evaluation with color doppler showed turbulent flow without significant stenosis (mean pressure gradient=13mmHg, peak pressure gradient=22mmHg). Aortic valve was bicuspid with moderate aortic regurgitation without stenosis. There was a raphe between left coronary cusp (LCC) and right coronary cusp (RCC). Ascending aorta diameter was normal. Evaluation for coarctation of aorta was negative. Mitral valve function was normal without stenosis or regurgitation. At examination, it was a blowing type diastolic murmur along with ejection sound and midsystolic murmur grade II at upper left sternal border (LSB). Despite these findings, patient was asymptomatic.