[A giant left atrial myxoma with severe mitral valve regurgitation: report of a case].

A 76-year-old female underwent operation with a diagnosis of a left atrial myxoma with accompanied mitral regurgitation. Although no clinical findings of mitral regurgitation were noticed preoperatively, degenerative changes to the anterior leaflet as well as chordae tendinae possibly due to mechanical damage by the movement of the giant tumor through the mitral valve complex were observed in operation. Resection of the tumor and mitral valve replacement were successfully performed. Our case suggests that it is indispensable to investigate the mitral valve during operation even in case of the left atrial tumor with no preoperative findings of mitral regurgitation.