Fine needle aspiration of rhabdomyosarcoma of the heart. Light and electron microscopic findings and histologic correlation.

Fine needle aspiration (FNA) biopsy was performed on a 12-year-old child with intractable cardiac arrhythmias and a mediastinal mass. The cytologic, immunocytochemical and electron microscopic findings on the aspirated material established an initial diagnosis of cardiac rhabdomyosarcoma. Subsequent histologic material confirmed the cytologic diagnosis. The findings are presented, and the use of FNA to definitively establish a preoperative diagnosis of cardiac rhabdomyosarcoma is discussed.