Primary cardiac rhabdomyosarcoma of the left atrium: an unusual presentation

Abstract

Rhabdomyosarcoma accounts for almost 20% of all primary malignant neoplasms of the heart. These tumors usually arise from the ventricular walls. In adult patients, they sometimes arise from the atrial walls and mimic atrioventricular valve stenosis. We describe a case of left atrial rhabdomyosarcoma that presented as severe mitral stenosis and required emergency surgery. The atrial mass was detected by transthoracic and transesophageal echocardiography, but only histopathology confirmed the nature of the lesion. Although rhabdomyosarcomas of the heart are highly lethal, operation is indicated for emergency cases, in order to clarify the diagnosis, relieve symptoms, and improve short-term survival.

Fig. 1 Internal surface of the neoplasm (in cross section): there are both necrotic and hemorrhagic areas. Arrows indicate obstruction of the right pulmonary veins.

Fig. 2A Tumor cells are roundish and have pleomorphic nuclei and large eosinophilic cytoplasm (H&E, ×340). Tadpole-shaped rhabdomyoblasts are visible.

Fig. 2B Diffuse intracytoplasmic reaction positive for desmin (immunoperoxidase stain for desmin, ×610).