Cardiac tamponade as a complication of bronchogenic cyst

Abstract

Bronchogenic cysts are rare incidental findings, but they can have life-threatening complications. Herein, we report a case of a 44-year-old man who presented with complaints of left-sided chest pain, intermittent dyspnea, and pink-tinged sputum. Computed tomography angiography of the chest revealed a large cystic mediastinal mass in the subcarinal location. During his hospital stay, the patient became hypotensive with jugular venous distention and muffled heart sounds on auscultation. A stat echocardiogram depicted a large pericardial effusion with early diastolic collapse of the right ventricle. Pericardiocentesis was performed for cardiac tamponade, followed by thoracotomy with removal of bronchogenic cyst. Herein, we highlight the relation between bronchogenic cysts and cardiac tamponade and review the surgical treatment options.

Bronchogenic cysts are relatively uncommon congenital lesions that are mostly asymptomatic or discovered as an incidental radiographic finding in adults.¹ When present, symptoms are usually caused by compression of the surrounding structures or are due to complications. Infection and rupture of the cyst into the trachea and pericardial and pleural cavity are the most common complications.² Herein we present a case of bronchogenic cyst complicated by development of cardiac tamponade.

CASE PRESENTATION

A 44-year-old man with known hypertension, asthma, and sleep apnea presented with chest pain, dyspnea, and pink-tinged sputum. Physical examination, basic laboratory tests, an electrocardiogram, and chest radiograph did not show any abnormalities. Computed tomography angiography scan of the chest showed an 8.9 × 9.4 cm middle mediastinal mass in the subcarinal location. The mass had a cystic component and appeared to compress the left atrium and surrounding pulmonary vasculature (Figure 1a, 1b). Magnetic resonance imaging of the chest revealed findings consistent with a bronchogenic cyst (Figure 1c). Thoracic surgery was planned for elective resection of the cystic mass.

Figure 1.

(a) Computed tomography of the chest showing the location of the bronchogenic cyst (red asterisk), which compresses the right superior (red arrow) and inferior (red arrowhead) pulmonary veins with decreased flow compared to left superior (white arrow) and inferior (white arrowhead) pulmonary veins. (b) A coronal image showing compression of the right pulmonary artery (arrowhead) by the bronchogenic cyst (asterisk). (c) A contrast-enhanced sagittal section of the magnetic resonance image of the chest showing compression of the left atrium (bottom star) by the bronchogenic cyst (top star). (d) A parasternal long-axis view on transthoracic echocardiogram showing pericardial effusion and collapse of the right ventricle.

A day before the operation, the patient had sudden-onset chest pain and dyspnea. Echocardiography showed a large circumferential pericardial effusion with evidence of exaggerated respiratory variation of mitral and tricuspid inflow, right ventricular early diastolic collapse, and a dilated inferior vena cava, findings supportive of cardiac tamponade (Figure 1d). Pericardiocentesis yielded 780 mL of yellow and hazy pericardial fluid, with an elevated white blood cell count of 2214 with 75% neutrophils. The patient was started on cefepime, vancomycin, and micafungin, which were later changed to ceftriaxone as fluid culture grew Propionibacterium acnes.

The patient underwent right video-assisted thoracic surgery (VATS), which had to be converted to a posterolateral thoracotomy (PTL) due to difficulty in attaining deep dissection. The pericardium appeared to have signs of inflammation. Inspection of the mass revealed that there was no space between the cystic mass and left atrium, major vessels, and mainstem bronchi. The cyst was unroofed, not completely resected, and a pericardial window was created. The patient’s postoperative course was uncomplicated, and he remained asymptomatic and hemodynamically stable with serial limited echocardiograms showing no re-collection of pericardial fluid. During surgery, multiple cultures from the cyst were obtained and remained negative. Histologic examination of a specimen from the cyst wall revealed respiratory epithelium with focal squamous metaplasia consistent with bronchogenic cyst as well as signs of acute and chronic inflammation with focal necrosis. The patient was discharged home with a plan to continue antibiotic therapy for 4 weeks.

DISCUSSION

Bronchogenic cysts, a rare anomalous budding of the ventral foregut, can occur at any point along the tracheobronchial tree. They most commonly occur in the mediastinum and account for up to 15% of mediastinal tumors and 60% of all mediastinal cysts.³ In symptomatic cases, the most common symptoms are cough, fever, pain, and dyspnea. About half of patients experience complications, most commonly infection, compression of the adjacent structures, and rupture into the surrounding cavities. Superior vena cava obstruction, pneumothorax, and dysphagia have also been reported, whereas malignancy and hemoptysis are very rare.^4,5

Bronchogenic cysts causing cardiac tamponade are sparsely mentioned in the literature, with most cases occurring due to rupture of the cyst into the pericardium, a direct compression effect of the cyst on the pericardium, or development of acute pericarditis due to infected bronchogenic cyst.^6–11 In our case, there were no clear signs of rupture or communication between the cyst and pericardium during surgical exploration. Hence, the cause of pericardial effusion is unclear. However, similar to our report, Kimura and Morita described a case of mediastinal bronchogenic cyst that caused pericardial effusion in a 58-year-old woman due to compression of the pericardium by the cyst and inflammation.¹² The location of the cyst is an important factor in compression. In a study by Ribet et al, 68% of the bronchogenic cysts around the tracheal bifurcation and hilum level caused symptomatic compression.¹³ In our case, the cyst was located just below the carina. Hence, it is possible that direct compression of the pericardium from the bronchogenic cyst caused pericardial effusion due to prolonged extrinsic pressure and decreased venous or lymphatic drainage. Pathologic examination of the cyst revealed signs of both active and chronic inflammation. Hence, we believe that the pericardium was directly affected by the inflammation within the cyst and contributed to collection of pericardial effusion.

A literature search showed six similar case reports. Yildiz et al reported on a case of a 17-year-old woman with a bronchogenic cyst who developed a pericardial effusion, with the pericardiocentesis aspirate growing Salmonella bredeney.⁶ Han et al reported on a 49-year-old woman who developed atrial fibrillation secondary to a pericardial effusion and a bronchogenic cyst. In this case, drainage of the pericardial fluid resolved the patient’s symptoms and atrial fibrillation, and cultures of the fluid were negative.⁷ Akin to our case, Smail et al converted from a VATS to an open thoracotomy in their surgical management of cardiac tamponade secondary to a pericardial effusion complicated by a bronchogenic cyst. Similarly, the surgeons had difficulty resecting the bronchogenic cystic margins via a VAT procedure, because the margins were adherent to the pericardium.⁸ Also, Gamrekeli et al and Benslimane et al reported on cases with cardiac tamponade secondary to recurrent bronchogenic cysts following drainage.^9,10 Another case was reported by Aggarwal et al in which cardiac tamponade was secondary to cyst rupture.¹¹

The general consensus is to pursue surgical resection in cases of suspected bronchogenic cyst. If left untreated, bronchogenic cysts in most adults become symptomatic, often with complications.¹³ Various surgical options are available, including mediastinoscopy, VATS, and PTL. Mediastinoscopy is relatively less invasive but achieves subtotal resection. Complete resection of the cyst is important to avoid recurrences; hence, use of mediastinoscopy as definitive treatment remains controversial.⁸ Both VATS and PTL are effective approaches for complete surgical resection of mediastinal bronchogenic cysts. Due to increasing operator experience, relatively better procedural outcomes, and decreased postoperative complications, recent studies have shown a preference for VATS over PTL.