Epipericardial fat necrosis

Epipericardial fat necrosis (also sometimes purely categorised as pericardial fat necrosis or epicardial fat necrosis) is a rare self-limiting cause of acute pleuritic pain in an otherwise healthy individual, without fever or cough. It occurs external to the pericardium.

Clinical presentation

The patient presents with acute pleuritic chest pain that may mimic other cardiopulmonary causes. It is a self-limiting pain, ipsilateral to the lesion, which is more commonly on the left side (can be right-sided). The pain may persist for several weeks. Syncope, tachycardia and dyspnoea have also been reported. However cough and fever are not seen ⁴.

On physical examination, a pericardial friction rub may be heard.

Laboratory findings, including inflammatory markers, and ECG are usually normal.

Pathology

The pathogenesis of pericardial fat necrosis is unknown. Some predisposing factors have been mentioned in the literature:

• trauma
• ischaemia due to an acute torsion
• high positioned pericardial fat
• obesity
• increased thoracic pressure related to the Valsalva manoeuvre may increase the capillary pressure, which leads to haemorrhagic necrosis

Radiographic features

Plain radiograph

Typically, the chest radiograph is normal in the first 48-72 hours of the disease. Following on from this a characteristic opacity is always seen ⁴:

• juxtacardiac mass-like opacity near the cardiophrenic angle with or without pleural effusion and ipsilateral to the chest pain
• it always lies ventrally and invariably merges imperceptibly with the heart border

CT

• ovoid encapsulated mediastinal (pericardial) fatty lesion with soft tissue rim and intrinsic and surrounding soft tissue stranding
• thickened adjacent epicardium
• a pleural effusion may be present

Findings are similar to that observed with epiploic appendagitis and omental torsion in the peritoneal space.

MRI

Findings on MRI have been reported in two patients, with findings reflecting those on CT, i.e. a fatty lesion and internal soft tissue stranding ⁴.

History and etymology

It is thought to have been first described in 1957 by Jackson et al ^4,8.

Treatment and prognosis

Conservative management with non-steroidal anti-inflammatory drugs (NSAIDs) and follow-up is usually performed. It is generally considered self-limiting. Historically, in the pre-CT era, many were removed due to concerns about malignancy ⁴.

Differential diagnosis

Possible differential considerations include:

• pericardial/epicardial lipoma
• pericardial/epicardial liposarcoma
• thymolipoma
• diaphragmatic hernia

Clinical differential diagnosis

Initially, when the chest radiograph is normal, it is often mistaken for more serious diagnoses that present with acute chest pain:

• acute pulmonary embolism (PE)
• acute myocardial infarction (AMI)