Pericardial cyst 입니다.

 

Pericardial cysts are an uncommon benign congenital anomaly in the middle mediastinum. They represent 6% of mediastinal masses, and 33% of mediastinal cysts. Other cysts in the mediastinum are bronchogenic – 34%, enteric – 12%, thymic and others – 21%

 

Pericardial cysts occur at the rate of 1 person per 100,000[2]. They are thought to result from failure of fusion of one of the mesenchymal lacunae that form the pericardial sac. Seventy five percent of them have no associated symptoms, and are usually found incidentally during routine chest x-ray or echocardiography. There have been about twenty reported cases of pericardial cysts presenting before the age of eighteen. Seventy percent of them are located at the right cardiophrenic angle, 22% in the left, and the rest are in the posterior or anterior superior mediastinum. The size varies from 2 to 28cm2. It is unknown if a particular size or position of the cyst corresponds to a higher rate of complications. If present, symptoms are usually due to compression of adjacent organs and include atypical chest pain, dyspnea, and persistent cough. Cardiac tamponade, obstruction of right main stem bronchus, and sudden death are the life threatening emergencies that have been reported. Cardiac tamponade is usually due to intra-pericardial rupture of the cyst, although tamponade due to spontaneous hemorrhage into the cyst has also been reported. Other reported complications include right ventricular outflow obstruction, inflammation and infection, pulmonary stenosis, partial erosion into adjacent structures, atrial fibrillation, and congestive heart failure. A few pericardial cysts resolve spontaneously, likely from rupture into the pleural space. The rates of spontaneous resolution or complications have not been reported.

 

On CT scan pericardial cysts are thin-walled, sharply defined, oval homogeneous masses . Their attenuation is slightly higher than water density – 30 to 40 HU.

 

The management of pericardial cysts includes observation, percutaneous drainage, and resection. Observation is possible with repeated CT scans. However, there is little information regarding the safety and appropriate length of observation. For high-risk patients, a non-operative strategy may be followed. The longest reported follow-up lasted twenty five years, and yielded a 2.5L cyst at the time of resection . Aspiration is another therapeutic option. One literature review reported that one third of patients had recurrence after percutaneous drainage at three years . Injection of a sclerosing agent such as alcohol decreases the likelihood of cyst recurrence.

The indications for resection of pericardial cysts include large size, symptoms, patient concern, uncertainty of malignant potential, and prevention of the life threatening emergencies. Before the development of thoracoscopy, thoracotomy was the approach of choice. Currently VATS is the approach most commonly used. The VATS approach has many accepted advantages over open procedures, including cosmesis, improved intra-operative visualization, shorter post-operative recovery, reduced pain, and patient preference.

 

While the morbidity and mortality of pericardial cysts are unknown, surgery has been demonstrated as the only definitive cure. Since operative risks of minimally invasive techniques are extremely low, it would seem reasonable to offer resection for all pericardial cysts in otherwise healthy patients for whom the risk of surgery is low.