Congenital Pericardial Defect

Clinical History

A 42-year-old man with intermittent chest pain on exertion and no relevant previous medical nor trauma history, was referred for calcium score evaluation and coronary computed tomography angiography (CCTA).
The patient had no relevant results on previous cardiac evaluations.
General physical examination was unremarkable.

Imaging Findings

Chest plain film showed levodisplacement of the heart and aortic knob with the trachea remaining at the midline (Fig.1).
Calcium score CT evaluation revealed a total calcium score of zero (Fig. 2). A few minutes later the patient underwent CCTA with prospective gating. The CCTA showed left rotation of the heart with posterior deviation (Fig.3).

Detailed evaluation of the CT images revealed partial defect of the left pericardium (Fig. 4).

Discussion

The pericardium is a two-layered membrane that envelops all four cardiac chambers and the origins of the great vessels [1]. The normal pericardium’s function is to: limit the spread of infection and inflammation from adjacent mediastinal structures; prevent excessive dilatation of the heart and reduce friction between the heart and surrounding structures [2].
Many disease processes can affect the pericardium, including infection, neoplasm, trauma, primary myocardial disease, and congenital disease [2-4].

Congenital defects of the pericardium are extremely rare anomalies. They occur due to premature atrophy of the cardinal veins during embryogenesis, which supply the pleuropericardial folds [3]. They are three times more common in males and may be associated with other congenital abnormalities such as bronchogenic cysts, atrial and ventricular septal defect, patent ductus arteriosus, mitral valve stenosis, tetralogy of Fallot and diaphragmatic hernia [2-4].

Although patients are often asymptomatic, symptoms may arise when cardiac structures are transiently entrapped or incarcerated in the defect due to the raised mobility of the heart [2-5].

Chest x-ray may reveal cardiac rotation (Fig.1) or cardiac silhouette abnormalities that may suggest the site of the defect causing and/ or herniation of pulmonary and cardiovascular structures [2-6].

On CT evaluation the normal pericardium is expressed as a dense line bordered by mediastinal and subepicardial fat, while the pathological pericardium is outlined by fluid or shows increased thickness/calcification [1, 3].

In the reported case, calcium score showed normal anatomy while CCTA showed levodisplacement and posterior rotation of the heart (Fig. 2, 3) thus confirming the intermittent character of the cardiac rotation/herniation through the left pericardium defect. Slight positional changes are helpful in diagnosing pericardial defects. The partial nature of the defect is confirmed by visualization of right-sided pericardium (Fig.5).

Direct evaluation of left-sided pericardial defects is extremely difficult due to the lung interface.
In clinical practice, this diagnosis relies on ancillary radiological signs such as: abnormal position of cardiac structures with excessive levorotation; cardiac indentation at the location of the defect and compression of the pulmonary veins and adjacent lung, as seen on the reported case (Fig. 4).

Complications of congenital pericardial defects may include herniation and entrapment of a cardiac chamber, infarction of the appendage, or compression of left coronary artery. [2, 3]. Surgical closure or enlargement of the defect is sometimes necessary [2].

Differential Diagnosis List

Final Diagnosis

Congenital partial absence of the pericardium

URL:	https://www.eurorad.org/case/13206
DOI:	10.1594/EURORAD/CASE.13206
ISSN:	1563-4086