Composite Hemangioendothelioma of the Right Atrium Presenting With Cardiac Tamponade in an Adolescent.

Primary cardiac vascular tumors are rare in children. We report a 14-year-old girl with hemorrhagic pericardial effusion, cardiac tamponade, and a large right atrial mass. Echocardiogram identified the lesion and tamponade physiology. Pericardial drainage and stabilization preceded computed tomography (CT) and cardiac magnetic resonance imaging. The mass was excised under cardiopulmonary bypass, and the atrial defect was reconstructed with an autologous pericardial patch. Histopathology and immunohistochemistry favored composite hemangioendothelioma of low malignant potential. Postoperative FDG PET-CT showed no residual or metastatic disease. Adjuvant gemcitabine/docetaxel-based chemotherapy was given after multidisciplinary review. Six-month echocardiogram showed no recurrence.