Multimodalities Imaging in Diagnosis of Pericardial Cyst

Abstract

Pericardial cysts, an uncommon benign congenital anomaly belonging to the category of mediastinal masses. Cysts are usually detected incidentally on chest radiography or echocardiography, being most patients asymptomatic. In some cases, however, symptoms and complications occur, like dyspnea, chest pain, or persistent cough. Computed tomography and magnetic resonance imaging are the imaging techniques of choice to diagnose pericardial cysts. The removal of pericardial cysts is restricted to the cases with an uncertain diagnosis or in the presence of symptoms.

INTRODUCTION

Pericardial cysts represent 5-7% of all mediastinal tumors.[1] They are considered to derive from failing fusion of one of the mesenchymal lacunae normally forming the pericardial sac. In some cases, pericardial cysts such as hydatid cyst and postinflammatory can be also acquired. The natural history of pericardial cyst is generally benign.[2] Usually, they are detected as incidental masses on chest X-ray. Frequently located at the right costophrenic angle and in only few cases at the left costophrenic, hilum or superior mediastinum.[3] Differential diagnosis of this chest radiographic finding includes malignant tumor, cardiac chamber enlargement, diaphragmatic hernia, and bronchogenic cyst.

CASE REPORT

A 43-year-old man, asymptomatic and affected by systemic hypertension treated with angiotensin-converting-enzyme-inhibitor, underwent routine echocardiogram at our department. He was asymptomatic.

On physical examinations, arterial blood pressure was 130/80 mmHg, heart rate was 70 beats per min; the patient was apyretic and on auscultation, neither cardiac murmur or pulmonary crackles and rales were found. Electrocardiogram showed sinus rhythm and nonspecific ST-T changes. Transthoracic two-dimensional echocardiography showed an abnormal posterior cystic structure [Figures 1 and 2], with diameters 9.8 cm × 6.2 cm [Figure 3] and area 41 cm² [Figure 4], with a soft inner septum; neither significant valvular abnormalities nor compression's images were identified. Transesophageal echocardiography, proposed for better characterization of the mass was refused by the patient. Three-dimensional echocardiography showed a structure composed of a cavity connected with the pericardial wall and an inner partition separating it into two communicating rooms [Figure 5]. Cardiac regenerative medicine (RM) was performed for differential diagnosis from other thoracic masses such as mediastinal tumors, hydatid cyst, etc. RM scans showed a large oval, homogenous mass adherent to the left-sided pericardium with thin, sharply demarcated walls, without contrast enhancement [Figure 6]. It appeared as nonenhanced, well-defined mass, adjacent to the pericardium, with low intensity on T1-weighted and high intensity on T2-weighted images [Figure 7].

Figure 1.

Echocardiography two-dimensional: parasternal long axis view. *Right ventricle; ^§Left ventricle; ^#Pericardial cyst

Figure 2.

Echocardiography two-dimensional: four chamber view. *Right ventricle; ^§Left ventricle; ^#Pericardial cyst

Figure 3.

Echocardiography two-dimensional: focus on cyst's diameters. 1# and 2# = Two chamber of the loculated cyst; °Soft inner septum

Figure 4.

Echocardiography two-dimensional: focus on cyst's area. ^§Left ventricle; ^#Pericardial cyst

Figure 5.

Echocardiography three-dimensional. 1# and 2# = Two chamber of the loculated cyst; °Soft inner septum

Figure 6.

Cardiac magnetic resonance imaging: T1- and T2-weighted images, different presentation of the cyst. *Pericardial cyst

Figure 7.

Cardiac magnetic resonance imaging four chamber view. *Pericardial cyst

Based on these findings, the mass was diagnosed as pericardial cyst; since the mass was not associated with symptoms or complications, a watchful waiting approach was followed. After 1-year follow-up, the patient remains asymptomatic.

DISCUSSION

Pericardial cysts are incidentally found in most cases. The diagnosis is frequently suspected due to abnormal findings on chest X-ray. Transthoracic echocardiography, computed tomography (CT), and magnetic resonance imaging (MRI) are the methods of choice for the diagnosis of pericardial cysts.[4] By performing apical and subxiphoideal views, on transthoracic echocardiography, it is possible to identify the characteristic aspect of the lesion, that is, an echolucent mass adjoining the cardiac border.[5] A loculated pericardial effusion can be confused for pericardial cyst, but the presence of a thin wall separating the cyst from the main pericardial space allows the correct differential diagnosis. The transesophageal echocardiogram plays a role in the more accurate identification of the localization of the mass or in the cases of inadequate transthoracic images. CT and MRI offer a more detailed description of localization. Usually, pericardial cysts fail to enhance in contrast imaging with both cardiac CT and MRI.[6]

The most frequent complications of pericardial cyst are the following: Sudden death, cardiac tamponade, rupture of the cyst, obstruction of the right ventricular outflow, pulmonary stenosis, erosion of the cyst into the superior vena cava and right ventricular wall, congestive heart failure, atrial fibrillation, pericarditis, and obstruction of the bronchi.[7] Management of pericardial cyst depends on cyst's characteristics and symptoms. Asymptomatic patients need radiological and clinical follow-up only, in fact, spontaneous resolution of pericardial cyst has also been observed.[8] Instead symptomatic patients or when cysts are large or local complications occur (especially in case of cyst infections) an interventional approach should be considered. The various treatment modalities include percutaneous aspiration of cyst, ethanol sclerosis, surgical resection, or video-assisted thoracoscopic surgery. Surgical excision becomes mandatory when pericardial cyst cause ventilator and/or hemodynamic impairment.[9]

Previous reports discuss the possibility of rupture of the cyst in a watchful waiting approach, but more thorough scientific documentation is required to confirm this.[10]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.