Epipericardial fat necrosis, the overlooked culprit behind chest pain: a case report

Abstract

Background

Epipericardial fat necrosis is a rare, self-limiting cause of acute chest pain, which is often misdiagnosed owing to its nonspecific presentation and it being a relatively unknown entity to radiologists.

Case presentation

A 58-year-old White Swiss male presented with pleuritic, position-dependent chest pain, dyspnea, and transient left-arm paresthesia. Initial workup showed mildly elevated troponins (38 ng/l) and left-sided pleural effusion on X-ray. Computed tomography imaging revealed an ovoid epipericardial fat lobule with surrounding edematous infiltration, consistent with epipericardial fat necrosis as the pain’s cause. Conservative management resulted in symptom resolution and discharge without complications.

Discussion

Epipericardial fat necrosis typically presents as an intense, pleuritic chest pain, often mimicking serious conditions such as pulmonary embolism or acute coronary syndrome. Computed tomography is the diagnostic modality of choice, frequently revealing a fat-density lesion with surrounding soft-tissue inflammation. Magnetic resonance imaging findings may include a fat-intensity lesion with inflammatory margins. While pathological evaluation is rarely needed, epipericardial fat necrosis may mimic malignancies, warranting careful follow-up in case of doubt. Treatment is conservative, focusing primarily on nonsteroidal anti-inflammatory drugs, and symptoms usually resolve within a week.

Conclusion

Epipericardial fat necrosis, though rare, should be considered in patients with unexplained chest pain and characteristic imaging findings. Awareness among radiologists and emergency clinicians is essential for accurate diagnosis and to avoid invasive interventions.

Introduction

Nonspecific chest pain is a common cause of presentation to the emergency department, accounting for 5.5% of admissions in the USA, often resulting in chest computed tomography (CT) scans [1]. A rare and often underdiagnosed cause of chest pain is epipericardial fat necrosis, which can result in localized pleuritic chest pain. The diagnosis can be made on chest CT but, owing to the rarity and little-known nature of this diagnosis, it often goes unnoticed during imaging studies [2, 3]. The pathology is self-limiting, with conservative management being the norm [4].

Case report

A 58-year-old White Swiss male presented to the emergency department after being sent by an outpatient unit. The patient had suffered from acute bradycardia, measured at 30 beats per minute, and fainted at the outpatient unit, leading to the staff beginning cardiopulmonary resuscitation and the administration of 1 mg of adrenaline. At the emergency department, he presented with pleuritic chest pain, varying in intensity, which he declared to have appeared the previous morning upon waking and had since been intensifying. The pain was described as oppressive, non-irradiating, and position-dependent, and it appeared upon palpation of the thoracic wall. The pain increased with effort. The patient also reported dyspnea and transitory paresthesia of the left arm.

The patient had a history of hypertension and psoriasis, and he smoked five cigarettes/day.

The patient had hypertension (143/79 mmHg) and a normal heart rate and saturation. An electrocardiogram (ECG) was performed, showing no anomalies. The patient’s laboratory results showed 77 mcmol/l of creatinine, slightly elevated troponins (9–21 to 38–38 ng/l), normal creatine kinase (CK), N-terminal pro-B-type natriuretic peptide (NT-proBNP) < 50 ng/l, and d-dimers < 241 ng/ml.

An X-ray was performed, showing a small amount of left-sided pleural effusion (Fig. 1).

Fig. 1.

Chest X-ray. Chest X-ray showing a small left-sided effusion (arrow)

The patient was diagnosed with non-ST-segment elevation myocardial infarction (NSTEMI) and hospitalized, with a chest CT being ordered for the following day.

The CT scan revealed significant coronary artery atheroma and left pleural effusion. Furthermore, the patient had a lobule of epipericardial fat that was surrounded by edematous infiltration of the soft tissue, leading to the diagnosis of epipericardial infarction and necrosis (Fig. 2).

Fig. 2.

Contrast-enhanced chest CT scan. Axial (A) and sagittal (B) contrast-enhanced chest CT showing an ovoid fat-density lesion (arrow) surrounded by infiltration of the surrounding tissue

It was determined that this was the cause of his pain, and the patient was discharged the following day, having recovered from the acute event.

No follow-up was required owing to the pathology’s self-limiting nature.

Discussion and conclusion

Epipericardial fat necrosis is a rarely diagnosed cause of chest pain, first described in 1957 [2, 3]. Although the exact pathophysiology is unknown, it is suspected to arise from the inflammation of pericardial mediastinal fat, likely due to torsion of a fat pedicle leading to vascular obstruction and adipose tissue necrosis, akin to what can be seen in abdominal epiploic torsion [3, 5]. Predisposing factors are thought to include obesity, trauma, high-positioned pericardial adipose, necrosis due to increased thoracic pressure, and structural anomalies [3, 6, 7]. A study found that 2.15% of patients who underwent an emergency department chest CT had epicardial fat necrosis, with a prevalence of 0.26% on chest CTs performed for any cause [8]. Some studies say that the prevalence is equal in males and females, whilst others claim that females are more likely to present with the condition [3, 4]. Age is not known to be a predisposing factor [7].

The clinical presentation is nonspecific, often being classified as pleuritic pain, ipsilateral to the lesion and usually on the left side [2, 3]. In some cases, the pain can irradiate to the upper body [3]. The pain is intense and may persist for weeks, with intermittent episodes for up to a year [3, 5]. The ECG and troponins will usually be normal [2, 3]. Owing to this nonspecific presentation, epipericardial fat necrosis (EFN) is often mistaken for life-threatening acute conditions such as acute pulmonary embolism, pneumothorax, acute aortic syndrome, pericarditis, or ischemic heart disease [3, 5, 7]. It is therefore important to think of EFN as a possible differential diagnosis when imaging patients with nonspecific thoracic pain in whom no other causes for the pain are found.

On chest X-ray, which is often the first modality used, EFN can present as an indistinct opacity along the mediastinum, possibly mimicking a mass-like lesion [4]. The case we presented is typical in this regard. CT imaging will generally demonstrate an ovoid fat-density lesion surrounded by soft tissue-density margins, as can also be seen in this case [3]. T1-weighted magnetic resonance imaging (MRI) will show a high-intensity lesion with a low signal rim [6]. T2-weighted MRI will show a lesion with the signal intensity of fat surrounded by an increased signal due to inflammation of the surrounding tissue [3]. There have been reports of slight gadolinium enhancement, suggestive of an inflammatory process [4]. Ancillary findings may include ipsilateral pleural effusion, which was present in our patient, pericardial thickening, and subsegmental atelectasis of the adjacent lung [3, 5]. A follow-up scan 4–8 weeks later can be performed to confirm healing and exclude malignancy [5, 7].

The differential diagnosis includes thymolipoma, diaphragmatic hernia, and pericardial lipoma and liposarcomas [3]. Thymolipomas can be differentiated, as they will appear as a mass arising from the mediastinum rather than a small ovoid lesion with peripheral infiltration [9]. Diaphragmatic hernias will be associated with a defect in the diaphragm and will not have any infiltration of the surrounding tissue [10]. It can be differentiated from lipomas as they are well encapsulated and do not have surrounding inflammation [11]. Liposarcomas will have a similar appearance but may have thick septations and are more likely to have calcifications [12].

Histopathology has been performed on certain lesions to rule out malignancy [4]. These lesions were adipose tissue macroscopically, with the microscopic aspect being that of inflammatory tissue, with different aspects depending on the stage of inflammation [4]. Early stage lesions have hemorrhage and necrosis, whilst later stages resemble granulation tissue [4]. It should be noted that histopathological analysis is rarely required, as radiological diagnosis, alongside clinical history, is normally sufficient to establish the diagnosis [5].

Treatment is conservative, usually relying on nonsteroidal anti-inflammatory medications, with pain often resolving within a week [3, 7]. However, severe cases can be treated with thoracic surgery to remove the painful lesion [3].

In conclusion, we presented a rare case of epipericardial fat necrosis (EFN), a similar phenomenon to abdominal epiploic appendagitis. EFN should be considered in cases of chest pain in healthy patients presenting with otherwise nonspecific symptoms. Radiologists should be aware of this diagnosis, as this entity can be readily diagnosed using chest CT and thus should be searched for in patients presenting to the emergency department with otherwise unexplained chest pain. Although histopathological analysis is required for a definitive diagnosis, radiology and clinical context are usually sufficient.

Abbreviation

EFN

Epipericardial fat necrosis

CT

Computed Tomography

ECG

Electrocardiogram

CK

Creatine Kinase

NT-proBNP

N-terminal pro-B-type natriuretic peptide

NSTEMI

non-ST-segment elevation myocardial infarction

MRI

magnetic resonance imaging

Author contributions

All authors contributed equally to the drafting, writing, and image acquisition. All authors read and approved the final manuscript.

Funding

Open access funding provided by University of Lausanne.

Data availability

Not applicable.

Declarations

Ethics approval and consent to participate

Ethics approval was acquired.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests

The authors have no competing interests to declare.