The authors report a case of a 16-year-old man who presented progressive dyspnea. At that time the diagnosis of rheumatic fever with mitral valve involvement was performed. The bidimensional echocardiogram showed presence of mobile mass inside the left atrium. The tumor presented lobules, projecting into the left ventricle during the diastole and provoking turbulence. The patient underwent surgical resection with postoperative course needing re-operation for mitral valve replacement. Histopathology has proven that such tumor was a primary cardiac rhabdomyosarcoma and the early clinical diagnosis of rheumatic mitral valve disease was very difficult.
Neoplasms; Heart valves; Mitral valve