Pulmonary sequestration

Keith A. Havenstrite, MD, MJ Barry, MD, TM Fitzpatrick, MD, PhD, FCCP, KM O'Neil, MD, FCCP--Walter Reed Army Medical Center and Uniformed Services University of the Health Sciences, Washington, DC, USA

Introduction: Bronchogenic cysts and pulmonary sequestrations are two of a group of cystic congenital pulmonary malformations that also includes cystic adenomatoid malformation and congenital lobar emphysema. Each may present prenatally through adulthood, either during an evaluation of specific symptoms or as an incidental radiologic finding. Here we describe a patient who was referred for treatment of both a bronchogenic cyst and a pulmonary sequestration. A review of the literature showed only two reports of similar cases.

Case Presentation: A 38 year-old Caucasian woman presented complaining of the recent onset of intermittent sharp left posterior thoracic pain and occasional dysphagia to solid food. There was no antecedent trauma. Physical examination and laboratory evaluation were normal. A chest radiograph (CXR) demonstrated a medial right lower lobe pulmonary density. Contrast-enhanced computed tomography (CT) of the chest showed a 5 X 5 centimeter (cm) predominantly cystic medial right lower lobe pulmonary lesion with drainage into the pulmonary venous system and arterial supply from the descending aorta. In addition, a 4 x 2 cm homogeneous cystic structure in the left superior visceral mediastinum was noted to be displacing the esophagus and trachea to the right. The CT and magnetic resonance imaging (MRI) of the chest were consistent with a right lower lobe pulmonary sequestration and left mediastinal bronchogenic cyst. Angiography confirmed systemic arterial blood supply to the right lower lobe lesion via a branch arising from the proximal celiac trunk. Venous drainage was into the right inferior pulmonary vein. Flexible fiberoptic bronchoscopy revealed normal airways. Excision of the symptomatic bronchogenic cyst was accomplished first via a left lateral thoracotomy. Histologic evaluation revealed a thin-walled cyst lined by ciliated respiratory epithelium. The pain and dysphagia have not recurred. Eight weeks later a right lower lobectomy was performed, with findings of an intralobar pulmonary sequestration supplied by two distinct systemic arteries. Her recovery has been uneventful.

Discussion: Bronchogenic cysts, which form secondary to abnormal budding of the tracheobronchial tree during airway development, are located most commonly in the mediastinum or within the pulmonary parenchtyma. Infrequently they are located in an intrapericardial or subdiaphragmatic position. These cysts contain mucoid material and are lined by ciliated columnar epithelium. Diagnosis is frequently delayed but can be made prenatally through adulthood. Two-thirds of patients eventually develop symptoms, which are related to infection or mechanical compression of the trachea or bronchi and include chronic cough, wheezing, stridor and recurrent pneumonia. Massive hemoptysis can occur due to intracyst hemorrhage via communication with the tracheobronchial tree, and malignant degeneration has been reported. Diagnosis is confirmed by the presence of a cystic mass on CXR, CT or MRI. Treatment consists of complete surgical excision, with segmentectomy or lobectomy as required for parenchymal lesions. Asymptomatic lesions should be excised to prevent the increased morbidity associated with the excision of symptomatic or complicated bronchogenic cysts. Pulmonary sequestration, which accounts for 0.15-6.4% of congenital pulmonary malformations, is a mass of abnormal pulmonary tissue without normal connection to the tracheobronchial tree. Its arterial supply arises from the systemic circulation. Extralobar sequestrations, which are contained in their own pleural envelope, frequently have systemic venous drainage, and associated anomalies are relatively common. In contrast, intralobar sequestrations, which are within the pulmonary parenchyma, typically drain into the pulmonary venous system, and associated anomalies are uncommon. With either type most patients are symptomatic from recurrent infection, mass effect or hemoptysis. Radiologic evaluation reveals variable cystic and solid components of the mass. Angiography may be required to delineate the arterial supply and venous drainage, although ultrasound in infants and CT or MRI may be adequate. Treatment is complete surgical excision.

Conclusion: Bronchogenic cysts and pulmonary sequestrations are congenital cystic abnormalities of pulmonary tissue with differing mechanisms of formation. Each may remain asymptomatic, but the majority will produce symptoms that lead to their diagnosis. Treatment is complete surgical excision with maximal preservation of functional pulmonary parenchyma. This is only the third reported case of a bronchogenic cyst and pulmonary sequestration presenting simultaneously.

References

[1] Cioffi U, et al: Presentation and surgical management of bronchogenic and esophageal duplication cysts in adults. Chest 1998; 113(6):1492-6

[2] Croyle P, Estrera AS: Bronchogenic cyst and intralobar sequestration mimicking thoracic aortic aneurysm. South Med J 1982; 75: 1267-8

[3] Grewal R, Yip C Intralobar pulmonary sequestration and mediastinal bronchogenic cyst. Thorax 1994; 49(6):615-6

[4] Nicolette LA, et al: Intralobar pulmonary sequestration: A clinical and pathological spectrum. J Pediatr Surg 1993; 28(6):802-5

[5] Nobuhara KK, et al: Bronchogenic cysts and esophageal duplications: Common origins and treatment. J Pediatr Surg 1997; 32(10): 1408-13

[6] Nuchtern JG, Harberg FJ: Congenital lung cysts. Semin Pediatr Surg 1994; 3(4):233-43

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