An Unusual Presentation of a Rare Case of Rhabdomyosarcoma of the Left Atrium as Severe Rheumatic Mitral Stenosis with Atrial Fibrillation, Fast Ventricular Rate, and Left Atrial Failure

It is extremely rare to encounter primary malignant tumors of the heart. Rhabdomyoma constitutes approximately 20% of all primary malignant tumors of the heart. Rhabdomyoma commonly arises from the ventricular wall, and rarely, they arise from the atrial wall and mimic symptomatic atrioventricular valve stenosis. We describe an extremely rare case of left atrial (LA) rhabdomyosarcoma detected during the transesophageal echocardiography arising from the posterior wall of the left atrium protruding into the left ventricle causing obstruction of the mitral valve. Our case is a rare case of LA rhabdomyosarcoma presenting with mitral inflow obstruction and symptomatically mimicking severe rheumatic mitral stenosis with atrial fibrillation and fast ventricular rate with orthopnea secondary to LA failure and passive pulmonary venous congestion.