Diagnosis of primary cardiac leiomyosarcoma by endomyocardial biopsy.

We report a case of a primary right ventricular leiomyosarcoma in a 58-year-old woman diagnosed by endomyocardial biopsy. Clinical findings included a 5-year history of atypical chest pain and atrial fibrillation as well as a 30-lb weight loss. A ventricular mass was identified by echocardiography and magnetic resonance imaging, and an endomyocardial biopsy was performed. Biopsy was guided by right ventriculography, which revealed a mobile mass in the cavity of the right ventricle. Light microscopy revealed a fasciculated, spindle cell sarcoma, most consistent with leiomyosarcoma, and immunohistochemical staining for muscle-specific actin was strongly positive in nearly all tumor cells, confirming its myogenous differentiation. Endomyocardial biopsy provided a definitive tissue diagnosis of this rare primary malignant cardiac neoplasm without the need for a surgical procedure.