Abstract
Large circumferential tumors encasing the heart are exceedingly rare, and the differential diagnosis include primary pericardial sarcomas, non-Hodgkin lymphoma, pericardial primitive neuroectodermal tumor, primary pericardial mesothelioma, and exceptionally mature benign lipoma. Lipomas are rare primary heart tumors. Most are epicardial in origin, although they may arise in the myocardium. They are usually soft masses of mature fat tissue encapsulated by a thin layer of fibrous tissue. Signs and symptoms depend on the tumor's location and size, however in several case they are found incidentally at cardiac imaging. In this 48-year-old woman referred to the emergency department for severe intestinal bleeding, echocardiography showed a large circumferential hypoechogenic space, and CT confirmed a large mediastinal fat mass encasing the heart. Multimodal imaging allowed differential diagnosis confirmed by histologic examination performed at surgery.