Primary cardiac synovial sarcoma originating from the mitral valve causing left ventricular outflow tract obstruction.

An 11-year-old boy was admitted due to different episodes of syncope and convulsion. Echocardiogram revealed a mass of 2 × 4 cm originating from the mitral subvalvular apparatus and more precisely from the antero-lateral papillary muscle, protruding in the left ventricle outflow tract causing intermittent obstruction. The patient underwent surgical excision of the left sided mass. Pathology confirmed the diagnosis of primary synovial sarcoma. At 6 months after the operation a small mass in the left ventricle of 1 × 1 cm was detected. The patient underwent reoperation consisting in radical resection of the subvalvular apparatus and mitral valve replacement. Histology confirmed that the mass was a cardiac synovial sarcoma. At 1 year after surgery the patient is doing well.