In this report, we describe a patient with two uncommon cardiac abnormalities: a subvalvular membrane in the left ventricular outflow tract and a cardiac fibroma (CF) in the left atrium. This 56-year-old patient presented with a known subaortic stenosis caused by a subvalvular membrane, a large mass attached to the interatrial septum in the immediate proximity of mitral valve, and a cardiac history of infective endocarditis. Initially, the mass was thought to be an old vegetation. However, the histology of this lesion diagnosed a CF. Primary cardiac tumors are rare. Myxoma and papillary fibroelastoma are the most frequently encountered primary cardiac tumors. CF is usually diagnosed during childhood. In this case, the presentation of the CF was atypical for 3 reasons: the tumor was diagnosed in an adult, the fibroma was pedunculated, and not located within the myocardium but originated from the interatrial septum.