Tracheal Agenesis and Atresia

Payne²³ first described congenital absence of the trachea in 1900. There have been fewer than 100 cases reported.²⁴ It represents a partial or complete absence of the trachea below the level of the normal larynx. This abnormality is incompatible with life if there is no connection of trachea or bronchi to the esophagus.²⁵ Floyd and others^26,27 classified three distinct types of tracheal agenesis (Fig. 9-1). In type I, the trachea originates from the esophagus, and the distal trachea, including the carina, is fairly normal; it represents 10% to 13% of the total number of tracheal agenesis cases. In type II, the trachea and carina are fused to the esophagus, and there is no residual trachea; this represents 59% to 62% of the total. In type III, the left and right main-stem bronchi originate from the esophagus, and there is no carina; this represents 22% to 31% of the total. Male incidence predominates in a 2:1 ratio. In 90% of the cases, there are other congenital lesions.²⁸ Tracheal agenesis may be associated with VACTERL (vertebral, anal, cardiac, tracheal, esophageal, renal, and limb patterns of congenital anomalies)²⁹ or with complex congenital heart defects as well as with upper extremity defects and duodenal atresia (referred to as TACRD).³⁰ It is believed that tracheal agenesis is the result of developmental failure of the laryngeal tracheal bud at the third to sixth week of development. The laryngeal tracheal groove fails to develop normally.

Figure 9–1 Tracheal agenesis classification. There are three types of tracheal agenesis: type I, the trachea originates from the esophagus rather than from the larynx; type II, no trachea is present and the carina originates from the esophagus; and type III, each main-stem bronchus originates from the esophagus.

(Modified from Haben CM, Rappaport JM Clarke KD. Tracheal agenesis. J Am Coll Surg 2002;194:217-22.)

Neonates present with severe respiratory distress and the inability to cry. Survival is unlikely, although there are two reported in the literature.^31,32 Those who are successfully managed are endoesophageally intubated,³³ with a nasogastric tube alongside the endotracheal tube for gastric decompression. Urgent bronchoscopy or tracheostomy may assist in diagnosis.^24,34 A survivor is described who had a type II defect and underwent esophageal intubation, gastrostomy, and distal esophageal banding.³¹ The patient is reported to have survived to 4 years, undergoing a colonic interposition at 3 years of age. A second patient is described with a type I defect who survived to 6 years of age.³² Extracorporeal membrane oxygenation (ECMO) may temporize these patients until a more definitive solution can be achieved.³⁵ If the patients can be stabilized, they should be examined for other life-threatening defects, such as neural and cardiac anomalies, that may require correction. The gastroesophageal continuity can be corrected with colonic interposition or gastric conduit, but there have been no attempts to reconstruct the trachea. Perhaps, for the future, to reconstruct the incompletely developed airway, tracheal allografts³⁶ or tissue-engineered replacements³⁷ may be used for long-term success.

Congenital Tracheal Stenosis

Congenital tracheal stenosis (Fig. 9-2) is rare. Cantrell and Guild³⁸ described three forms of stenosis. Type I is stenosis of the full length of the trachea. Type II is a funnel-shaped stenosis of the upper, lower, or entire trachea. Type III is a segmental stenosis of the lower trachea. This classification assists in identifying patients who are more likely to have associated anomalies and in planning treatment. Stenotic regions have complete cartilaginous rings, the number of which is variable, anywhere from 2 to 18. This rare anomaly is associated with pulmonary vascular sling or vascular ring in 50% of cases.³⁹ A functional classification system has been proposed to assist in selection of the operative candidate.^40,41

Figure 9–2 Tracheal stenosis (stovepipe trachea) in a 20-month-old boy with stridor since birth. Frontal chest radiograph shows a diffusely narrowed trachea faintly outlined by water-soluble contrast medium.

(Courtesy of Simon C. Kao, MD, Iowa City, IA.)

These patients usually have exertional wheezing or stridor after birth. The type II and type III abnormalities are associated with anomalous location of one more bronchi, most likely a left pulmonary artery sling. All three types are associated with pulmonary agenesis. Symptoms vary according to the degree of stenosis. Patients presenting during the neonatal period or infancy with severe stridor, cyanosis, and recurrent stridor have the highest mortality. Many of these patients have associated congenital malformations and infections. Their prognosis even after surgical correction is variable.⁴⁰ Other children presenting at a year of age or soon thereafter have a surgical mortality of 10% to 20%.⁴² Some children, late in childhood or early teens, may present for an evaluation for asthma with varying degrees of exertional dyspnea. Typically, these children have a better prognosis. CT, especially multiple detector CT, provides enough detail to assess the tracheobronchial abnormality with a sensitivity of 90%, better than flexible bronchoscopy,⁴³ and any associated anomalies. Bronchoscopy aids in diagnosis, treatment planning, and evaluation of the surgical repair intraoperatively and postoperatively. Echocardiography is helpful to assess for cardiac and vascular anomalies. Patients should be aggressively treated because they are at high risk for sudden death without surgical correction.⁴⁴ Partial tracheal resection is the most frequently performed operation. The neonatal trachea does not tolerate tension as well as in the adult.⁴⁵ Up to 50% of the infant trachea can be resected with primary reanastomosis. The repair is much more difficult if more than 50% of the trachea or the carina is involved.

In 1964, the first repair, a primary resection and end-to-end anastomosis, was reported by Cantrell and Guild.³⁸ Reconstruction has been performed with pericardium,⁴⁶ aortic homograft,⁴⁷ costochondral graft,⁴⁸ slide tracheoplasty (Fig. 9-3),^49,50 and tracheal autograft.⁵¹ Complete repair of the tracheal stenosis and any vascular ring or sling requires cardiopulmonary bypass and potential circulatory arrest. Backer and coworkers⁵² reviewed their 18-year experience in 50 patients, comparing four tracheal stenosis repair techniques: pericardial patch, primary resection, tracheal autograft, and slide tracheoplasty. They concluded that when eight or fewer rings are involved, primary resection is preferable. For stenosis longer than eight rings, an autograft is better. Vascular endothelial growth factor application has the potential of improving the results of tracheal autograft.⁵³ In contrast, Muraji⁵⁴ demonstrated that the slide tracheoplasty technique allowed early extubation and an excellent long-term result in one case. ECMO may be necessary to support the neonate postoperatively.^35,48 Long-term outcome after resection appears to result in normal growth and development.⁵⁵ For patients who are considered surgically uncorrectable, palliative maneuvers include balloon dilation and split posterior tracheoplasty,^56,57 stenting, local steroid injection, electroresection, and cryotherapy.^40,41

Figure 9–3 Congenital tracheal stenosis. A, After identification of the area of stenosis, the midportion of the stenosis is transected, leaving two halves of the trachea disconnected. B, A longitudinal tracheal incision is then made in each half, the full length of the stenosis, posterior in the upper half and anterior in the lower half. The corners are trimmed to allow an even, uncrimped anastomosis. C, Stay sutures help in retraction and alignment. D and E, The anastomosis results in an oblique suture line. The resultant cross-sectional area is quadrupled.

(Modified from the Society of Thoracic Surgeons. Ann Thorac Surg 1994;58:613-21.)

Tracheomalacia

In tracheomalacia, weakened cartilage collapses on expiration. With inspiration, there is sufficient suspension of the tracheal wall to maintain patency. The most common pathologic finding is oval rather than round cartilaginous rings. There is a congenital and an acquired form of tracheomalacia. The congenital form can be diffuse and both proximal and distal, involving the main-stem bronchi. It is associated with tracheoesophageal fistula.^58,59 The more common acquired form results from degeneration of the cartilaginous support, usually by vascular compression such as from a vascular ring or sling, adjacent inflammatory process, tumor, or chest wall deformity (e.g., pectus excavatum).

Tracheomalacia is not usually manifested at birth. It worsens as the child grows, usually after several weeks of life. Coughing, respiratory distress, severe dyspnea, stridor, and cyanosis may occur. Acute apnea, referred to as dying spells, is the most severe presentation. Dyspnea worsens with agitation or respiratory tract infections. These severe symptoms should prompt further investigation.

One fourth of all esophageal atresia patients have tracheomalacia. Tracheoscopy, bronchoscopy, esophagoscopy, and esophagography may be necessary for complete evaluation. CT and MRI provide additional information. The differential includes normal pulsatile collapse, bronchial webs, and tracheal tumors. Many patients suspected of having tracheomalacia may instead have gastroesophageal reflux disease or reflux disease in addition to tracheomalacia. This may warrant either a trial of a proton pump inhibitor and prokinetic agent or a formal evaluation for reflux.⁶⁰

Tracheomalacia improves with age in most cases. “Dying spells,” inability to be weaned from the ventilator, and failure to thrive are indications for more aggressive therapy. If tracheomalacia is mild, the infant should be supported and observed because infants usually outgrow their tracheomalacia within the next 2 years. In more severe forms, mortality is as high as 80% with conservative management. Stents have been used with varying success to allow cartilage maturation, usually taking several months.^61,62 Tracheostomy also has been used but is associated with some complications.⁶³ Aortopexy (Fig. 9-4), by itself or with tracheal resection or stenting, has been performed by a left submammary thoracotomy through the third interspace. The thymus is preserved. After exposure of the ascending aorta, three or four nonabsorbable sutures are placed through the aortic adventitia above and below the innominate artery takeoff. These sutures are attached to the periosteum. Finally, the endotracheal result is visualized by intraoperative bronchoscopy. Eighty percent of the patients are extubated by 4 weeks, and the long-term results are good.⁶⁴ The acquired form is treated similarly to the congenital form. Longer segment lesions without vascular compression often require tracheostomy and mechanical ventilation for a time. Bronchomalacia may require both aortopexy and pulmonary artery pexy.⁶⁵

Figure 9–4 Tracheomalacia and aortopexy. In patients with severe tracheomalacia and aortopexy, suturing of the proximal transverse–ascending aorta to the anterior chest wall or sternum may significantly improve the obstructive symptoms.

(Modified from Weber TR, Keller MS, Fiore A. Aortic suspension [aortopexy] for severe tracheomalacia in infants and children. Am J Surg 2002;184:573-77.)

Bronchial Atresia

Bronchial atresia, first described by Ramsay in 1953,⁶⁹ is the second most common abnormality of the airway after tracheoesophageal fistula. A lobar or segmental bronchus ends blindly in the lung tissue. Lung tissue distal to the bronchial atresia expands and becomes emphysematous as a result of air entering through the pores of Kohn.⁷⁰ Beyond the atretic segment but proximal to the hyperinflated lung, the terminal airway is mucus filled. It is believed that the bronchial bud somehow separates distally from the proximal bronchial bud and continues to develop. Another potential explanation is that there is a vascular insult of the airway in the atretic segment. In either case, the distal airway continues to develop normally.

Infants usually develop respiratory distress 4 or 5 days to several weeks after birth. They may have wheezing, stridor, and repeated pulmonary infections. The most common location is in the left upper lobe, then the left lower lobe, followed by the right upper lobe. A segmental bronchus rather than a lobar bronchus is atretic, most frequently presenting as a lung mass on the first chest radiograph of the newborn. Fetal lung fluid is slowly absorbed, becoming a localized translucency with an opaque circular or oval density at the hilum. Patients rarely mature to adulthood without investigation.

For better assessment of this abnormality, a CT scan should be performed.^71,72 Prenatal diagnosis by ultrasonography has been reported.⁷³ The differential diagnosis includes acquired bronchial stenosis (which may result from long-term intubation), bronchial adenoma, sequestration, mucoid impaction, vascular compression syndrome, Swyer-James syndrome, and atypical bronchogenic cyst.

Indications for resection in bronchial atresia include a recurrent and possibly serious pulmonary infection, respiratory distress, and increasing size of the translucent lung.⁷⁴ Some resect the abnormal tissue to prevent infection. Segmentectomy is possible, but lobectomy is usually required.

Congenital Bronchiectasis

Bronchiectasis is an abnormal dilation of the bronchi or bronchioles. It is believed to be secondary to failure of the mesenchyme to differentiate into cartilage and muscle.⁷⁵ It results in a chronic, mildly productive cough with recurrent pneumonia. CT usually achieves the diagnosis,⁷⁶ and bronchoscopy typically is unnecessary. Bronchography also is unnecessary, given the detail provided by CT. Treatment and prognosis depend on the number of segments or lobes involved. Patients are provided with humidity, chest physiotherapy, and oxygen as necessary. Therapeutic bronchoscopy is performed for suspected mucoid obstruction or bleeding. Bleeding is initially controlled by embolization, topical epinephrine, or intravenous pitressin. Oral, intravenous, and nebulized antibiotics may be helpful in controlling symptoms.⁷⁷ Patients who have localized congenital symptomatic bronchiectasis may require a segmentectomy, lobectomy, or possibly pneumonectomy. The success of surgical intervention is related to the ability to resect all the diseased lung.⁷⁸

Tracheobronchomegaly (Mounier-Kuhn Syndrome)

Tracheobronchomegaly was first described in 1932 by Mounier-Kuhn.⁷⁹ It is characterized by excessive dilation of the trachea and main bronchi (Fig. 9-5).⁸⁰ This dilation is the result of atrophy of the elastic tissue and smooth muscle of the trachea and main-stem airways.⁸¹ Airway dilation continues to third-order subdivisions. During the course of the disease, mucosal herniations develop between tracheal rings, creating a diverticulosis pattern. Associated conditions include cutis laxa, Ehlers-Danlos syndrome, Marfan syndrome, Kenny-Caffey syndrome, ataxia-telangiectasia, ankylosing spondylitis, Brachmann–de Lange syndrome, and light chain deposition disease. When an isolated process occurs, there is recessive inheritance.⁸² Tracheobronchomegaly also may result from severe pulmonary fibrosis with increased traction on the tracheal wall.^83,84 As these diverticula develop, there is mucus retention with resultant development of bronchiectasis and fibrosis. Patients eventually are unable to clear secretions and succumb to chronic infection and respiratory failure.

Figure 9–5 Tracheobronchomegaly (Mounier-Kuhn syndrome) in a 13-year-old girl with chronic cough and bronchiectasis. CT scan at the level of the trachea (A) and main-stem bronchi (B) shows air-filled saccules (arrows) around the airway from chronic inflammation destroying the normal elastic properties of the tracheobronchial tree and its smooth muscles.

(Courtesy of Simon C. Kao, MD, Iowa City, IA.)

The patients are usually men in their third to fourth decades of life. Fifty percent of patients with tracheobronchomegaly have no symptoms until their third decade. They usually have recurrent lower respiratory tract infections. Asymptomatic patients may be identified in that the trachea is three standard deviations larger than normal; for adults, it exceeds 3 cm.⁸⁵ Patients with tracheobronchomegaly frequently have recurrent respiratory tract infections and persistent cough. Plain chest radiography demonstrates an enlarged trachea and main-stem airways that may be ectatic. CT more clearly demonstrates changes, and tracheal dimensions for adults⁸⁶ and children⁸⁷ are helpful in making the diagnosis. Bronchography may be necessary to differentiate it from acquired bronchiectasis. Bronchoscopy generally is unrewarding, with inadequate visualization of the airway lumen as a result of multiple tracheal wall diverticula.

In general, there is no surgical role in the treatment of tracheobronchomegaly. Management of secretions helps minimize the symptoms. Stenting and T-tubes^88,89 may provide significant palliation. Recently, a successful double-lung transplantation with bilateral bronchial stents for tracheobronchomegaly has been reported.⁹⁰

Laryngotracheoesophageal Cleft

Laryngotracheoesophageal cleft is a rare congenital abnormality resulting from failure of the esophagus to separate from the laryngotrachea⁹¹; infants have a toneless cry and choke with feeding. On an attempt to pass a nasogastric tube, a communication with the airway is seen. A barium study or endoscopy can demonstrate the fistula. One half to more than three fourths of patients survive.^92,93 With late detection, mortality is high. Patients are first treated with a gastrostomy. Then, through a cervical approach, the fistula is divided, the esophagus and larynx are repaired, and a muscle flap is placed between them to reduce likelihood for recurrence. A nasogastric stent is left in place for a time. For large defects, a combined cervical and thoracic approach may be necessary.⁹⁴

Tracheobronchial-Esophageal Fistula

Tracheobronchial-esophageal fistula (TEF) is the most common abnormality of the trachea, occurring in 2.4 per 10,000 births.⁹⁵ The most commonly used anatomic classification system for TEF is the one proposed by Gross.⁹⁶ type A, esophageal atresia without TEF; type B, esophageal atresia with proximal TEF; type C, atresia with distal TEF; type D, atresia with both proximal and distal TEF; and type E, TEF without esophageal atresia (H-type). Type C is the most common, accounting for 87% of the anomalies, followed by type A (8%), type E (4%), type B (1%), and type D (1%). Associated congenital defects are common⁹⁷; cardiovascular anomalies lead the list, with concomitant occurrence in 35% of TEF cases. In about 20% of cases, TEF occurs as part of the VACTERL constellation of defects.

Patients present with feeding difficulties and excessive salivation. Intermittent cyanosis and tracheobronchial infections are seen as well. Diagnosis of the most common form (type C) is suspected when a large amount of air is seen in the esophagus, stomach, and small bowel. Failure of nasogastric tube passage and its position on plain radiography or contrast fluoroscopy confirm the condition. Cameron Haight is credited with the first successful pediatric TEF repair.⁹⁸ Although it was initially accomplished through left thoracotomy, Haight came to prefer right extrapleural thoracotomy for division of the fistula and esophageal anastomosis. Esophageal anastomotic leak is seen in about 15% of cases, but with a functioning chest tube in proximity, 95% of leaks heal spontaneously.⁹⁹ Subsequent stricture formation is common, but it generally responds well to dilation. Major, life-threatening leaks occasionally occur. In this situation or in the case of so-called long-gap atresia, wherein esophageal continuity cannot be established despite a variety of elongation techniques, esophageal replacement by colonic interposition or gastric transposition may be necessary. Even in critically ill neonates with a substantial esophageal anastomotic leak, gastric pull-up has been successfully applied as an alternative to temporizing with wide drainage alone.¹⁰⁰ Long-term outcome after surgery for TEF has been the subject of several recent reviews.^101–103

For ligation of the H-type fistula, a right neck incision is made, allowing avoidance of the thoracic duct. The sternocleidomastoid muscle and carotid sheath contents are retracted laterally. The recurrent laryngeal nerve is identified and protected, and the fistula is divided and oversewn. An interposition muscle flap reduces the likelihood of recurrence. TEF recurrence has been successfully managed with a minimally invasive technique. In one pediatric series, the fistula tracts were de-epithelialized by fulgurating diathermy under endoscopic guidance, with successful track obliteration by way of fibrin glue application.¹⁰⁴ For the lower-lying H-type fistula not accessible through a cervical incision, thoracoscopic ligation has been successful.^105,106

Not surprisingly, minimally invasive techniques have been increasingly applied not only to management of fistula obliteration but to esophageal reconstruction as well.^107–109 Thoracoscopic repair has been accomplished through an extrapleural approach,¹¹⁰ and even long-gap esophageal atresia has been amenable to the thoracoscopic approach. The latter consists of initial thoracoscopically mediated esophageal traction followed by staged thoracoscopic creation of the esophageal anastomosis.¹¹¹ Nuances of anesthetic and intensive management of neonates undergoing thoracoscopy and laparoscopy are becoming better appreciated.^112,113 Meticulous anesthetic management has allowed successful TEF repair in a neonate with single-ventricle physiology (unpalliated tricuspid atresia).¹¹⁴

Preservation of the azygos vein, previously divided with impunity during repairs of esophageal atresia and TEF, has been advanced as desirable. The theory is that postoperative mediastinal edema may be avoided, thereby minimizing esophageal anastomotic complications.^115,116 Clinical significance of this concept awaits further evaluation.

Bronchobiliary Fistula

Bronchobiliary fistula (Fig. 9-6) is a very rare congenital abnormality with perhaps fewer than 50 cases reported.¹¹⁷ It has generally been reported in infants and children, but a number of cases have been diagnosed in adulthood.^118–120 The fistula track is composed of bronchial and biliary-type tissue from its origin in the airway to the liver. Patients produce green sputum and develop dyspnea and chronic cough. Infants may present with respiratory distress¹²¹; girls are more commonly affected. The right middle lobe and right main-stem airways are most frequently involved and usually drain to the left hepatic ductal system. Associated anomalies, although not the rule, include esophageal atresia and TEF,¹²² biliary atresia,¹²³ and right-sided diaphragmatic hernia.¹¹⁷

Figure 9–6 Bronchobiliary fistula. In this child with bilious sputum and a congenital diaphragmatic defect, a fistula was found between the right main-stem bronchus and the biliary tree.

(Modified from DiFiore JW, Alexander F. Congenital bronchobiliary fistula in association with right-sided congenital diaphragmatic hernia. J Pediatr Surg 2002;37:1208-09.)

Diagnosis is made by bronchoscopy, during which a catheter may be passed into the fistula for administration of contrast material and concomitant radiography.¹²⁴ This represents a more modern form of bronchography. Diagnosis also has been achieved with a nuclear biliary scan (^99mTc-HIDA cholescintigraphy)^125,126; this is useful for postoperative surveillance as well. Finally, MRI for neonatal diagnosis has been reported, emphasizing the utility of T1-weighted gradient-echo sequences.¹²⁷

Patients with a confirmed bronchobiliary fistula are treated by ligation and division of the fistula, transecting it as close to the airway as possible. Pulmonary resection has been necessary on occasion.¹¹⁹ Access is by way of transpleural or extrapleural right thoracotomy. Cholecystography is used selectively to verify biliary drainage into the duodenum.¹²⁶ For those with impaired prograde biliary drainage or biliary sepsis, hepatic lobectomy (generally left-sided) or Roux-en-Y hepaticojejunostomy may be necessary.¹²⁸

Bronchopulmonary Foregut Malformations

Bronchopulmonary foregut malformations represent another category of congenital lung diseases. The classification includes sequestrations (intralobar and extralobar), bronchogenic cysts, and other less common entities.

Bronchopulmonary foregut malformations are an abnormal communication between normal lung and esophagus or stomach and represent the second most frequent abnormal communication between the airway and intestinal tract, tracheoesophageal fistula being the most common. Right and left lower lobes are equally and most commonly affected. The fistula rarely involves the gastric fundus or mid-esophagus, almost always tracking to the lower esophagus. It is associated with extralobar sequestrations, more often on the left side. Diagnosis is usually made in the first few months of life up to 18 years of age. The most useful diagnostic test is esophagography. These malformations are associated with other anomalies, such as diaphragmatic hernia and cardiac, gastrointestinal, or vertebral anomalies. Because of chronic infection, lobectomy is usually necessary, and the fistulous communication must be divided and the esophageal defect repaired. If there is no evidence of infection, lung tissue may be preserved.

Sequestrations

Sequestrations are lung defects that have systematic arterial blood supply and abnormal bronchial connections. They are invariably located in the base of the lung, with males more frequently affected than females by a 3:1 ratio. Intralobar sequestrations (Fig. 9-7) are cystic abnormalities within the visceral pleural covering of the lung, whereas extralobar sequestrations (Rokitansky’s lobe; Fig. 9-8) are mass lesions that have their own separate visceral covering. Intralobar sequestrations represent 75% of all sequestrations. As a group, intralobar sequestrations receive vascular blood supply from the thoracic aorta in 74% of cases, from the abdominal aorta in 19% of cases, from the intercostals in 3% of cases, and from multiple sources in 20% of cases. The aberrant blood supply most commonly enters the anomalous lung away from the hilum. The venous drainage of sequestrations is usually through pulmonary veins, but it may be through systemic veins. Intralobar sequestration is most frequently found within the posterior segment of the left lower lobe.

Figure 9–7 Intralobar pulmonary sequestration. A, Frontal chest radiograph shows consolidation of the left lower lobe. B, CT image of lung base shows opacification of the left posterior lower lobe. C, Contrast-enhanced magnetic resonance angiogram shows that a large arterial branch (arrow) arising from the low thoracic aorta supplies this region.

(Courtesy of Koji Takahashi, MD, Asahikawa Medical College, Asahikawa, Japan.)

Figure 9–8 Extralobar sequestration. Extralobar sequestration is most frequently found in the lower left chest with its own pleural investment and systemic venous drainage. CT scan is beneficial in better identifying the anatomic details of the defect.

(From Singh SP, Nath H. A 53-year-old man with hemoptysis. Chest 2001;120:298-301.)

Extralobar sequestrations are rounded, smooth, soft masses that usually lie just above the dome of the diaphragm; 90% occur at the base of the left lung. The venous drainage of extralobar sequestrations occurs most frequently through the systemic circulation, to either azygos or hemiazygos systems; only 20% of cases demonstrate venous drainage into the pulmonary veins. On microscopic examination, all lung structures are present in extralobar sequestrations, including alveoli, bronchi, and cartilage.

Intralobar and extralobar sequestrations are both derived from foregut tissue and thus may possess an esophageal fistula. Intralobar sequestrations may present in utero as polyhydramnios or may become symptomatic in adolescents or young adults. Repeated bouts of pulmonary infection and hemoptysis are the most common symptoms. Intralobar sequestration is rarely associated with other congenital anomalies; extralobar sequestration is not uncommonly associated with other anomalies, especially congenital diaphragmatic hernias. Extralobar sequestrations may be found within either the pericardium or the diaphragm or beneath the diaphragm retroperitoneally. Malignant neoplasms have been reported within extralobar sequestrations, and a simultaneous discovery of congenital cystic adenomatoid malformation has been reported, as have other anomalies such as pericardial cysts, esophageal achalasia, and cardiac defects. In the absence of malignant disease, patients with both intralobar and extralobar sequestrations may demonstrate marked serum elevations of the tumor markers CEA and CA19-9.¹²⁹

CT is sensitive and specific for identification of either intralobar or extralobar sequestrations. MRI may be helpful.¹³⁰ Bronchography and bronchoscopy are less likely to provide additional information. Barium esophagography may be necessary to demonstrate an esophageal communication. Angiography is seldom necessary, because noninvasive studies generally demonstrate the feeding systemic vessels.

Many lesions are discovered prenatally, and careful follow-up is recommended. If hydropic changes are noted, delivery is indicated.^131,132 In infants, cysts that are large or cause hemodynamic compromise may be temporarily drained by needle aspiration or tube thoracostomy to allow adequate induction of anesthesia. If no infection is involved, the cyst alone, or possibly a segment, may be removed. In most cases, however, lobectomy is required. Early identification of the aberrant arterial blood supply is critical and helps avoid disastrous bleeding. Most of the arteries are less than 1 mm in diameter, but some have been reported to be as large as 2.5 mm. Atherosclerotic changes in the systemic artery may make it difficult to manipulate during surgery. A communication with the gastrointestinal tract should be thoroughly searched for at the time of surgery. Venous drainage also may be aberrant, and it should be ascertained before resection, if possible. Both intralobar and extralobar sequestrations may be amenable to resection by minimally invasive techniques. The outcomes after resection are excellent.^133,134