Cardiac tumors, whether primary (mostly benign) or secondary (metastatic), are extremely rare, and very few cases of retiniform hemangioendothelioma have been documented since its initial diagnosis in 1994. We present a 67-year-old male who presented with pericarditis, recurrent pericardial and pleural effusions. On computed axial tomography, an oval lesion located on the superior aspect of the left pulmonary pericardial recess within the transverse sinus, adjacent to the trunk of the pulmonary artery. In the operating room, after dissection and resection of the mass, the histopathological diagnosis of retiniform hemangioendothelioma was confirmed.