Intrapericardial lymphangioma presenting as neonatal cardiac tamponade.

We report a unique case of cardiac tamponade in a newborn due to an intrapericardial lymphangioma. Echocardiography and magnetic resonance imaging suggested that the mass, which was situated between the right atrium and the aortic root, was unsuitable for primary resection. A pericardial window was performed, and over the next 16 months the tumor spontaneously regressed.