The incidence of pericardial cysts is about 1 per 100,000 (
1). Pericardial cysts are uncommon benign congenital lesions in the middle mediastinum ( 1, 4).
Most of the masses in the middle mediastinum (61%) are cysts (
1, 5). Pericardial cysts and also bronchogenic cysts are the second most common masses after lymphomas ( 1). Other cysts in the mediastinum are bronchogenic (34%), enteric (12%), thymic and others (21%) ( 1, 4).
Pericardial cysts (or benign mesothelial cysts), are uncommon lesions that are often found incidentally. There is no sex predilection (
6). Their formation may result from failure of fusion of one of the mesenchymal lacunae that form the pericardial sac ( 6). On histologic examination, the cyst wall is composed of fibrous tissue lined by mesothelium, like normal pericardium, with mild chronic inflammation ( 6).
Most of them are asymptomatic (50% - 75%) and found incidentally during routine chest X-ray or echocardiography (
2). Additional diagnostic methods include trans-thoracic echocardiography, CT scan and magnetic resonance imaging (MRI). The frequency of follow up imaging has not been established yet ( 7). Contrast-enhanced CT scan has been the modality of choice for diagnosis and follow-up ( 3). On CT scan, the pericardial cyst is thin-walled, sharply defined, and an oval homogeneous mass. Their attenuation is slightly higher than water density (30 - 40 HU). Pericardial cysts do not enhance with intravenous contrast ( 7). Pericardial cyst calcification or rupture occurs rarely ( 4).
The diagnosis usually is suspected following abnormal findings on chest radiography, showing bulging of the right heart border. Additional diagnostic modalities that may find pericardial cysts include transthoracic echocardiography, CT, and MRI of the chest (
3, 5, 8).
The age distribution is not well defined. Twenty reported cases of pericardial cysts in literatures presented before the age of eighteen (
1), but most of the articles reported older patients.
Pericardial cysts are usually unilocular, smooth, and smaller than 3 cm in diameter (
5). Cyst size varies from 2 to 28 cm ( 1). In our patient, the cyst size was 13 × 8 × 5 cm in diameter that is one of the largest cysts we have found in the literature ( 9) ( Table 1).
Table 1. Summary of Published Giant Pericardial Cyst Case Reports
Reference Publication Year Age, y Gender Size, cm Location Presenting Symptom Treatment Present study 2015 24 Male 13 × 8 × 5 Right side Dyspnea and persistent cough Surgical excision with median sternotomy Simsek et al. ( 10 ) 2014 28 Male 6.4 × 9 Right side Fever, sore throat, dry cough, pleuritic chest pain Conservative management Hamad et al. ( 11 ) 2013 30 Male 11.2 × 7.4 Right side Weight loss(15 Kg), palpitation,chest pain Surgical treatment Forouzandeh et al. ( 12 ) 2012 71 Female 8 × 5 Right side Dyspnea, cough, fever Video-assisted thoracoscopic excision Celik et al. ( 13 ) 2012 54 Male 6.5 × 4.7 Left side Acute coronary symptom Surgical resection and bypass operation(CABG) at the same time Kaklikkaya ( 9 ) 2011 39 Male 22 × 15 × 7 Left side Several episodes of left pleuritic chest pain Left side thoracotomy Kumar et al. ( 14 ) 2011 5 Male (child) 10 × 9.5 × 9 Right side Chest pain, cough, fever Surgical excision with median sternotomy Thanneer et al. ( 15 ) 2011 22 Female 21.5 × 11.4 × 14.2 Behind the heart in posterior mediastinum Syncope Needle aspiration Matono et al. ( 16 ) 2010 38 Male 12 × 10 Right side Asymptomatic and excised because of rapid growing after 20 years Video-assisted thoracoscopic excision Neizel et al. ( 17 ) 2010 59 Female Approximately 5 × 5 intrathoracic mass behind the heart Atrial flutter and presyncope Excision with surgery Pereira et al. ( 18 ) 2008 73 Female 14 × 10 × 7 Right and anterior and left side of heart Retrosternal pain Referred for surgery but was not operated Nina et al. ( 19 ) 2007 44 Female 13 × 9.5 Right side Progressive exertional dyspnea, right side chest pain, dry cough Right side thoracotomy Dernellis et al. ( 20 ) 2001 27 Female 15.6 × 12.2 × 5.6 Right side Asymptomatic Surgical removal (the reason for referral for surgery was not mentioned)
CT scan with contrast has been the diagnostic modality of choice to follow asymptomatic patients with pericardial cysts (
1). However, no studies have shown the superiority of contrast CT over MRI and echocardiography for diagnosis or follow-up. On CT scan, pericardial cysts are thin-walled, sharp, oval homogeneous masses. Their attenuation is slightly higher than water density (30 to 40 HU) ( 2). Their enhancement with intravenous contrast is poor ( 2).The frequency of follow-up imaging has not been defined.
Management of pericardial cysts depends on their symptom. If the patient is asymptomatic, serial echocardiography is enough, but if the patient is symptomatic or reveals an increase in the size of the cyst or has solid component in the cyst cavity in the serial follow-up,a cyst resection has been the most favored approach [with thoracotomy or sternotomy or video-assisted thoracic surgery (VATS)] (
3, 5). Aspiration is another method, but one-third of the patients have shown recurrence.
Non-operative strategy may be selected for high-risk patients. The longest reported follow-up lasted twenty five years. Cyst aspiration is another therapeutic option. One literature review reported that about 30% of the patients had recurrence after percutaneous drainage at three years. Sclerosis has been reported to decrease recurrence rate after aspiration (
Morbidity and mortality are low. Surgery has been demonstrated as the only definitive curative treatment (