A 49-year-old female patient was referred to Chungnam National University Hospital with anterior chest pain, palpitations, and shortness of breath that had lasted for 5 days prior to her visit. The patient had no specific medical history. The results of a complete blood count, a blood chemistry panel, and electrolyte testing were within the normal limits, and no sign of infection was observed. An electrocardiogram showed a normal sinus rhythm, and a chest X-ray showed an enlarged cardiac silhouette and mild bilateral pleural effusion. Echocardiography showed a very large cystic mass compressing the posterior wall of the left atrium, and a large amount of pericardial effusion caused a diastolic collapse of the ventricles that was consistent with cardiac tamponade. A computed tomography scan of the chest revealed a 9-cm, round, homogeneous cystic mass with well-defined margins in the subcarinal area. The cyst compressed the left atrium, left main bronchus, and pulmonary veins, and displaced the pulmonary veins . An emergency right-sided thoracotomy was performed because of the sudden onset of atrial fibrillation, low blood pressure, and aggravated dyspnea. The cystic mass was located in the subcarinal area and compressed the left atrium anteriorly. After peri-cardiotomy and aspiration of the content of the cyst, the atrial fibrillation ceased, and the patient’s blood pressure increased. The cyst was radically resected, but a part of the cyst wall remained that was densely attached to the left atrium and major vessels. There was no connection between the cyst and the pericardial cavity. The pericardial effusion was transudate, but no microorganisms were identified in the fluid. Pathological analysis showed that the mass was a bronchogenic cyst. The patient did not have any complications and was discharged 12 days following the operation. She had no recurrence of symptoms such as palpitations or dyspnea, and there was no recurrence of the cyst or pericardial effusion during 5 years of follow-up visits.

Bronchogenic cysts are rare malformations that usually develop in the tracheal branches of the mediastinum or the pulmonary parenchyma. The mediastinum is the most common site of bronchogenic cysts. Most bronchogenic cysts are diagnosed incidentally because patients do not show symptoms . However, they sometimes bring about life-threatening complications associated with infections, rupture, hemorrhage, and compression of the surrounding structures. Bronchogenic cysts causing cardiac tamponade are extremely rare, and most such cases occurred due to rupture of the bronchogenic cyst into the pericardium. The present case showed a huge bronchogenic cyst causing compression of the left atrium and pulmonary veins, and a large amount of pericardial effusion. However, unlike previous reports, the origin of pericardial effusion was not from the ruptured bronchogenic cyst. There was no communication between the bronchogenic cyst and the pericardium, and the serous pericardial effusion was distinguished from the fluid in the cyst. We hypothesized that the pericardial effusion might have been due to hemodynamic changes caused by compression of the left atrium and pulmonary veins.

The choice of treatment of bronchogenic cysts is surgical resection . There are various surgical options, such as mediastinoscopy, video-assisted thoracoscopic surgery (VATS), or thoracotomy according to the condition of the patient . A huge cyst can safely be excised by VATS after mediastinoscopic drainage. In the present case, our strategy was to perform a right-sided thoracotomy because of the sudden onset of atrial fibrillation, hypotension, and the possibility of an unexpected hazardous condition. VATS can be a good surgical option for decompression and excision of the cyst because it enables a quick approach to the mass, even in a patient with a compromised cardiovascular condition. However, the surgical approach was carefully considered because of general limitations as well as considerations specific to this case, such as a thickened cystic wall, severe adhesion to the surrounding structures, and the possibility of unexpected hazardous conditions that could be caused by the pericardial effusion remaining in the cavity.

A huge bronchogenic cyst causing compression of the surrounding structures can develop into a life-threatening condition such as cardiac tamponade. Early surgical resection is a good treatment option, and the surgical approach should be determined based on a consideration of the condition of the patient, the characteristics of the mass, and the possibility of other unexpected conditions.