Hypoplasia of the posterior mitral leaflet: A rare cause of mitral regurgitation in adulthood.

Hypoplasia of the posterior mitral valve leaflet (PMVL) is a rare congenital heart disease, usually presenting in infancy and childhood with severe mitral regurgitation, either in isolation or associated with other cardiac lesions. We report a case of a 69-year-old woman with recent-onset exertional dyspnea and severe mitral regurgitation. Two- and three-dimensional transesophageal echocardiography showed severe hypoplasia of the PMVL, confirmed by surgical inspection.