Contributed by
Vanderbilt University Medical Center
Zoey Duncan, MD , and Jessica Leschied, MD.
History
14-year-old female presents to the cardiologist with sharp, stabbing left sided chest pain. D-dimer 0.57. EKG, troponin and echo were normal.
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Question
What is the most likely diagnosis?
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Correct answer
Epicardial Fat Necrosis
Discussion
Epicardial fat necrosis (EFN) is a self-limiting condition of the mediastinal fat surrounding the heart. EFN frequently presents with acute chest pain, often pleuritic, and associated precordium tenderness. EFN frequently mimics more serious cardiopulmonary disease processes such as pulmonary embolism, acute coronary syndrome, and aortic dissection.
On CT pulmonary angiography, no pulmonary arterial filling defect was identified to suggest pulmonary embolism. However, a lesion anterior to the thymus with internal fat density was identified.
Further characterization with MRI was performed, showing 1cm T1 hyperintense mass within the anterior mediastinum, with low signal dropout on the out of phase imaging along the periphery, confirming complete fatty composition. On post contrast images, there is minimal enhancement surrounding the lesion and extending along the left pleural surface, consistent with inflammatory changes.
The pathophysiology of EFN is not fully elucidated. Proposed theories include acute torsion of a vascular pedicle supplying a fatty appendage of the epicardial fat, resulting in ischemia and subsequent fat necrosis. Underlying structural abnormalities including lipoma or hamartoma may be a predisposing factor.
Differential diagnosis
Pericardial Lipoma – Fat containing lesion that can be found in the pericardial space. Expected findings include smooth, well circumscribed margin and homogenous fat attenuation.
Liposarcoma – Lesion will classically demonstrate internal nodularity and irregular septations with enhancement of solid components.
Thymolipoma – Often occurs at the cardiophrenic angle and will display fat interspersed with thymic tissue.
Diaphragmatic hernia with herniation of fat – diaphragmatic defect with intra-abdominal herniation of fat.
References
- Lee HH, Ryu DS, Jung SS, Jung SM, Choi SJ, Shin DH. MRI findings of pericardial fat necrosis: case report. Korean J Radiol. 2011 May-Jun;12(3):390-4. doi: 10.3348/kjr.2011.12.3.390. Epub 2011 Apr 25. PMID: 21603300; PMCID: PMC3088858.
- Barreto I, Oliveira FG, Barreira SC, Inácio JR. Epipericardial fat necrosis in chest CT and MRI: a case report of an unusual cause of chest pain associated with the initial diagnosis of undifferentiated connective tissue disease. BMC Cardiovasc Disord. 2023 Jun 22;23(1):314. doi: 10.1186/s12872-023-03349-x. PMID: 37349709; PMCID: PMC10286368.
- Giassi Kde S, Costa AN, Bachion GH, Apanavicius A, Filho JR, Kairalla RA, Lynch DA. Epipericardial fat necrosis: an underdiagnosed condition. Br J Radiol. 2014 Jun;87(1038):20140118. doi: 10.1259/bjr.20140118. Epub 2014 Apr 8. PMID: 24707937; PMCID: PMC4075564.
- Amălinei C, Grigoraş A, Balan RA, Rîşcanu LA, Giuşcă SE, Căruntu ID. Thymolipoma - the frontier between hamartoma and neoplasia? Rom J Morphol Embryol. 2021 Jul-Sep;62(3):651-661. doi: 10.47162/RJME.62.3.01. PMID: 35263392; PMCID: PMC9019679.