Mediastinal (Epipericardial) Fat Necrosis: An Overlooked and Little Known Cause of Acute Chest Pain Mimicking Acute Coronary Syndrome.

Necrosis of the fat adjacent to the heart, referred to as pericardial fat necrosis, epipericardial fat necrosis, and mediastinal fat necrosis, is a rare, self-limited condition. It presents as a sudden onset of severe chest pain that mimics symptoms of pulmonary embolism and acute coronary syndrome. Computed tomography (CT) findings are quite typical and consist of a round- or oval-shaped mass-like lesion containing soft tissue and fat density components in the cardiophrenic space. Lack of familiarity with this condition has led in the past to surgical interventions to remove the mass-like mediastinal fat necrosis. Until the early 2000s, surgical removal of these lesions was deemed the treatment of choice, to exclude a neoplasm. However, the observation that the CT findings of the paracardiac mass resemble fat necrosis seen in other parts of the body and its involution on follow-up CT has led to the realization that the process is a benign and self-limiting one. A dramatic shift in the paradigm of treatment has ensued and surgical treatment is no longer advocated. Awareness of this condition is, therefore, vital so as to diagnose it accurately and avoid unnecessary future surgical interventions.