[Huge left atrial myxoma masking the severity of mitral regurgitation; report of a case].

It is well known that mobile or large left atrial myxoma may lead to valve obstruction and insufficiency, and affect transmitral valve flow. A 50-year-old woman with a huge left atrial myxoma occluding the mitral valve was reported. The tumor was diagnosed by preoperative echocardiogram and mitral regurgitation was minimum. During the operation and after the myxoma resection, a severe mitral regurgitation, which was not observed during the preoperative echocardiogram, was noticed. Mitral valve defect was corrected by an annuloplasty ring, and the patient had an uneventful recovery. Our case suggests that careful evaluation of mitral valve during a myxoma resection operation is recommended.