[A case of mitral valve prolapse simulating mitral tumor or vegetation].

We observed a case of mitral valve prolapse (MVP) mimicking mitral tumor or vegetation. The patient was a 34-year-old man. He complained of palpitation and precordial oppression. Shaggy and mass echoes of the anterior mitral valve were recorded by M-mode and two-dimensional echocardiograms. The "mass" echo was confirmed to by originated in a markedly myxomatous change of the spongiosa layer of the mitral valve at operation. These problems on echocardiographic diagnosis of MVP and mitral "mass", such as mitral tumor or vegetation, were discussed in detail.