Pericardial cysts are uncommon benign congenital anomalies of the anterior and middle mediastinum.
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Clinical presentation
Patients are usually asymptomatic and these cysts are usually discovered incidentally although occasionally may present with chest pain and dyspnoea ref.
Pathology
Pericardial cysts are thought to often result from aberrations in the formation of coelomic cavities. They can occur as sequelae of previous pericarditis. The cyst wall is composed of connective tissue and a single layer of mesothelial cells and usually contains clear fluid ref.
Location
They are most commonly found on the right, in particular the right anterior cardiophrenic angle, but can be found almost anywhere adjacent to the heart including the left cardiophrenic angle, and the anterior or posterior mediastinum 10.
Variants
Radiographic features
Plain radiograph
Typically seen as a mass-like density at the cardiophrenic sulcus. They can be of different shapes and are not always round. May change in shape and size with inspiration and position.
CT
Usually appears as a well-defined, non-enhancing, fluid-attenuation, rounded mass next to the pericardium.
MRI
Morphology again can be variable. Internal septations may be present. Signal characteristics are those of fluid and include 4:
T1: typically low signal (occasionally can be high signal if contains proteinaceous material)
T2: high signal
T1 C+ (Gd): no enhancement
Treatment and prognosis
They are benign lesions. Surgical resection or aspiration may be performed for symptomatic selected cases 6,7.
Differential diagnosis
As general differential on cross-sectional imaging
On a chest radiograph also consider: