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ORIGINAL ARTICLE |
Thoracic Surgery Unit, Department of Cardiothoracic and Vascular Surgery, Siena University Hospital, Siena, Italy
Felice Granato, MD, Tel: +39 32 098 5926, Fax: +39 057 758 6140, Email: felicegranato{at}yahoo.it, Azienda Ospedaliera Universitaria Senese, Dipartimento di del Cuore dei Vasi e del Torace, Unità Operativa Complessa Chirurgia Toracica, viale Bracci 14, CAP 53100, Siena (SI), Italy.
ABSTRACT
A few cases of major complications after surgery for bronchogenic cyst have been reported. The purpose of this study was to analyze the complicated and unusual cases among 30 consecutive patients with bronchogenic cysts treated surgically at our institution between 1975 and 2007. There were 3 cases of mediastinal bronchogenic cyst characterized by significant surgical complications or very unusual pathological findings. The operations were performed through a thoracotomy in 25 patients, and by video-assisted thoracoscopic surgery in 5. Two patients suffered iatrogenic injury of the contralateral main bronchus during excision of a mediastinal cyst; in one of them, late development of foreign body granuloma was related to migration towards the bronchial wall of cyanoacrylate used to reinforce suturing of the bronchial tear. Histological examination of one resected specimen showed a large-cell anaplastic carcinoma arising from the wall of a mediastinal bronchogenic cyst. Bronchogenic cysts should be excised before they become symptomatic or infected, which leads to more difficult surgery and complications. The small risk of developing malignancy within a bronchogenic cyst also justifies early intervention.
Key Words: Bronchogenic Cyst • Foreign Bodies • Mediastinal Cyst • Mediastinal Emphysema • Thoracic Surgery • Video-Assisted
INTRODUCTION
Bronchogenic cysts are lesions arising from abnormal budding of the tracheobronchial tree. They develop from the ventral primitive foregut between the 26th and 40th days of gestation, and are the most common primary cysts of the mediastinum. Depending on the timing of abnormal development, cysts may locate within the mediastinum (mediatinal cysts) or lung parenchyma (intrapulmonary cysts). Although some bronchogenic cysts are asymptomatic and diagnosed as incidental findings on radiographs, most are associated with clinical symptoms such as coughing, dyspnea, chest pain, and sputum.1 A few cases of major complications have been reported after surgery for bronchogenic cyst.2 The purpose of this retrospective study was to analyse the complicated and unusual cases among 30 consecutive patients who underwent resection of bronchogenic cysts.
PATIENTS AND METHODS
We reviewed the operative reports and pathological findings of all 30 patients (18 men and 12 women) with a median age of 45 years (range, 18–65 years) who underwent resection of a bronchogenic cyst at the Thoracic Surgery Unit of Siena University Hospital during the 32-year period from 1975 to 2007. The patients were divided into 2 groups according to the localization of the cyst: mediastinal (n =20) or intra-pulmonary (n =10). We describe and analyze separately 3 cases of mediastinal bronchogenic cyst characterized by significant surgical complications or very unusual pathological findings.
CASE 1
A 24-year-old man underwent a right thoracotomy for resection of a mediastinal bronchogenic cyst measuring 6 x 6 cm. The cyst was easily peeled from the main right bronchus and esophagus, but showed severe pericardial adhesions, leading to incomplete excision. Twenty-six years later, the patient was again referred to our hospital because of cough, fever, and abnormal enlargement of the mediastinum on chest radiography. Computed tomography (CT) demonstrated a cystic mass containing fluid in the posterior mediastinum (Figure 1
). A decision was made to proceed with surgical removal of the recurrent bronchogenic cyst. A right redo thoracotomy was performed, and a mucoid cyst with severe adhesions to the bronchial carina, esophagus, right pulmonary artery, and pericardium was found. Sharp dissection of the cystic wall from the bronchial wall led to contralateral damage of the main bronchus. The damage was repaired with nonabsorbable sutures, and covered by applying cyanoacrylate and an autologous flap of parietal pleura. Histological findings of the specimen confirmed the diagnosis of bronchogenic cyst. Three years later, the patient underwent chest CT because of increasingly severe cough. The scan revealed almost complete occlusion of the left main bronchus. At bronchoscopic evaluation, the internal surface of the left main bronchus showed a foreign body granuloma, and on the opposite side, a stone-like vegetation containing a suture (Figure 2). Laser cauterization of the granuloma and partial removal of the foreign body was achieved by rigid bronchoscopy. Microscopic examination of the specimen identified the foreign matter as cyanoacrylate. Complete removal of the cyanoacrylate was achieved after several endoscopic sessions (Figure 3), thus preventing the development of a bronchial fistula.
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CASE 3
A 15-year-old girl was admitted because of cough, fever, and dyspnea. After radiological evaluation showed a mediastinal bronchogenic cyst, surgery was performed via video-assisted thoracoscopy through the right 6th intercostal space in the midaxillary line. This revealed a whitish mass of 4 cm in diameter, wrapped in mediastinal pleura, and establishing severe adhesions to the bronchial bifurcation. Two additional ports were inserted to perform thoracoscopic excision of the cyst. As the cyst adhered strongly to the contralateral main bronchus, the cystic wall was separated from the bronchial wall using sharp detachment procedures, which led to bronchial injury. The damage site was promptly identified, and the surgical procedure was converted to a limited right thoracotomy. Repair of the bronchial tear was achieved with nonabsorbable blanket sutures, and the mass was completely removed. One year later, follow-up CT revealed pneumomediastinum (Figure 4), and subsequent bronchoscopy identified a small fistula at the pars membranacea of the left main bronchus; the patient had reported asthmatic attacks. She underwent a left thoracotomy without identification of the suspected fistula. The pars membranacea of the left main bronchus was covered by applying an autologous pericardium flap. Some months later, the patient still complained of asthmatic attacks, although less frequent. A series of bronchoscopies was performed, revealing a congenital cystic adenomatoid malformation of the left main bronchus, which behaved like migrating self-repairing micro-fistulas, and limited pneumomediastinum. We believe that the second intervention considerably reduced the clinical manifestations of the disease. Resection of the left main bronchus with end-to-end reconstruction was suggested to achieve complete resolution.
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The patients’ clinical features according to disease localization are summarized in Table 1. Of the 30 patients, 9 (30%) presented with symptoms. Cough was the most common symptom, occurring in 8 (26%) patients. The incidence of symptoms varied significantly between patients with mediastinal cysts (3, 15%) and those with intrapulmonary cysts (6, 60%). CT was performed in 25 patients, and found to be useful in defining the localization of cysts and their relationship to adjacent structures, although it was of limited value in determining the characteristics of cystic contents. In particular, 6 (20%) patients showed high-density cystic contents, suggesting a solid tumour. Ten patients underwent both CT and magnetic resonance imaging. In all cases, a preoperative diagnosis of bronchogenic cyst was made. In patients who showed a high-density mass on CT, T1- and T2-weighted images revealed the pure serous cystic content. Surgical procedures, operative findings, and complications are listed in Table 2. Extensive mediastinal adhesions to adjacent organs were found in 4 (20%) cases. All patients with intrapulmonary cysts underwent surgical excision through a thoracotomy. No complications were observed during these interventions.
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Surgery has been advocated as the treatment of choice for bronchogenic cysts. There is general consensus on the need for surgery in symptomatic patients, but controversy still remains regarding asymptomatic cases.1,3 Even though cysts may remain silent forever in some patients, once symptoms arise, surgery is definitely not easy because of complicating anatomic factors.1 In our series, 2 mediastinal cysts in symptomatic patients were associated with severe adhesions to adjacent organs. The sharp dissection required in these cases led to bronchial damage with the necessity for re-intervention and repair. This bronchial damage was thought to be related to an inflammatory state due to infection and fistulization, which generated strong adhesions between the bronchial and cystic walls. In at least one patient (case no. 3), there was a cystic malformation of the left main bronchus wall, which led to development of a primitive bronchogenic cyst and a subsequent mucosal canal disorder, behaving like fistulous bronchial disease.
Concerning malignant transformation, there are some reports with convincing evidence of the development of carcinoma within a bronchogenic cyst.4,5 In this study, we found a rare case of large-cell anaplastic carcinoma arising from the wall of a bronchogenic cyst. Complete excision of bronchogenic cysts is usually achievable, and is considered essential to prevent recurrences. When this is not possible, ablation of the epithelial layer should be performed by removal of the cystic mucosa or electrocoagulation.6,7 There are a few reports of recurrent bronchogenic cysts associated with re-intervention after incomplete excision.7 We had a case of incomplete extirpation of a mediastinal cyst, leading to a very late recurrence. At the time of the first intervention, removal or electrocoagulation of the residual wall was not undertaken to avoid malignant arrhythmias, because of its pericardial localization.
We observed a previously unreported case of migration of cyanoacrylate towards the bronchial wall. Endoscopic use of cyanoacrylate in the conservative repair of bronchial fistula after pneumonectomy is well-known;8 however, only Sabanathan and collegues9 have described the application of cyanoacrylate in pulmonary resections to reinforce the sutured bronchial stump or anastomosis without complications. In our case, the sealing agent was used to repair an iatrogenic injury of the left main bronchus, which occurred after re-intervention for late recurrence. This material was found subsequently in the bronchial lumen, associated with a foreign body granuloma. Re-canalization of the left main bronchus was achieved after several bronchoscopic applications of an argon laser.
We believe that in adults, as in the pediatric population, bronchogenic cysts should be excised without waiting until they become symptomatic or infected, which might entail more complex surgery and incur a greater risk of complications. The small risk of developing a malignancy from a bronchogenic cyst also justifies intervention at the time of diagnosis. We do not recommend the routine use of a thick layer of cyanoacrylate in elective surgery, because some patients may develop a foreign body reaction with serious consequences.
REFERENCES
Asian Cardiovasc Thorac Ann 2009;
17:467-471
© 2009 by SAGE Publications
DOI: 10.1177/0218492309343855
This article has been cited by other articles:
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  J. Lesaffer, B. Heremans, P. De Leyn, and D. Van Raemdonck Video-assisted mediastinoscopic resection of a large symptomatic bronchogenic cyst Interact CardioVasc Thorac Surg, June 1, 2011; 12(6): 1071 - 1073. [Abstract] [Full Text] [PDF]
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B. Kirmani, B. Kirmani, and F. Sogliani Should asymptomatic bronchogenic cysts in adults be treated conservatively or with surgery? Interact CardioVasc Thorac Surg, November 1, 2010; 11(5): 649 - 659. [Abstract] [Full Text] [PDF]
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F. Granato, L. Luzzi, L. Voltolini, and G. Gotti Video-assisted mediastinoscopic resection of two bronchogenic cysts: a novel approach Interact CardioVasc Thorac Surg, September 1, 2010; 11(3): 335 - 336. [Abstract] [Full Text] [PDF]
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