Blood Cyst of the Mitral Valve Echocardiographic and Magnetic Resonance Imaging Diagnosis

A 12-year-old, apparently healthy woman was referred to the echocardiography laboratory as part of evaluation of school physical control. Physical examination was unremarkable. Two-dimensional echocardiography showed a large (14×15×18 mm), nonechogenic, rounded, thin-walled cystic mass attached to the atrial surface of the anterior mitral valve leaflet (Figure [A] and [B]; Movie I in the Data Supplement). Apical 4-chamber view showed normal ventricular size and function (Movie II in the Data Supplement), without left ventricular inflow tract …