HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only All Versions of this Article: e17v1 24/1/e17    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Berrocal, T. Articles by Gómez-León, N. Search for Related Content PubMed PubMed Citation Articles by Berrocal, T. Articles by Gómez-León, N.

Congenital Anomalies of the Tracheobronchial Tree, Lung, and Mediastinum: Embryology, Radiology, and Pathology¹

¹ From the Department of Pediatric Radiology, Hospital Infantil La Paz, 261 Paseo de la Castellana, 28046 Madrid, Spain. Presented as an educational exhibit at the 2002 RSNA scientific assembly. Received April 21, 2003, revision requested July 2, revision received and accepted August 13. Address correspondence to T.B. (e-mail: cprieto@hulp.insalud.es).

	Abstract

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 
Congenital anomalies of the chest are an important cause of morbidity in infants, children, and even adults. The evaluation of affected patients frequently requires multiple imaging modalities to diagnose the anomaly and plan surgical correction. The authors analyze and illustrate practical aspects of certain common and uncommon congenital anomalies affecting the tracheobronchial tree, lung, and mediastinum, with emphasis on radiologic manifestations. Other thoracic anomalies such as rib anomalies and vascular rings are discussed when they are associated with anomalies of the tracheobronchial tree. The usefulness of the various imaging modalities in the diagnosis and treatment of these conditions is also evaluated. Specific topics addressed include tracheal conditions such as tracheal stenosis, tracheomalacia, tracheal bronchus, tracheal atresia, and bronchogenic cyst; anomalies of the lung such as lung underdevelopment (agenesis and hypoplasia), scimitar syndrome, congenital cystic adenomatoid malformation, congenital lobar emphysema, and pulmonary sequestration; esophageal anomalies such as esophageal atresia, tracheoesophageal fistula, and esophageal duplications; and vascular rings. The embryologic and pathologic basis of the radiologic findings are discussed in appropriate cases. Differential diagnoses, as well as pitfalls and diagnostic difficulties, are included.

© RSNA, 2003

Index Terms: Bronchi, abnormalities, 671.1412, 671.1441, 671.1499 • Esophagus, abnormalities, 71.141, 71.142 • Lung, abnormalities, 60.141, 60.142, 60.145, 60.146, 60.1499 • Trachea, abnormalities, 671.1493, 671.1499 • Trachea, stenosis or obstruction, 671.1414, 671.1499

	Embryology

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 
The respiratory system develops from the ventral wall of the foregut during gestation at 3–4 weeks (embryonic stage) and continues development during the first 2 years of life and beyond. The epithelium of the trachea, bronchi, and alveoli originates from the endoderm; muscle, cartilage, and connective tissue originate from the mesoderm (1,2). The tracheobronchial tree develops between days 24 and 36 of gestation. A median bulge develops on the ventral wall of the pharynx at the laryngotracheal groove at days 24–26 (3). While the laryngotracheal groove is forming, there is a proliferation of the mesenchyme of the primitive mesentery (mediastinum); from this mesenchyme, the cartilage, muscle, and connective tissue of the lungs will develop (2). By the 28th day, the bulge has formed into the right and left lung buds. As the lung buds elongate, lateral invagination of the mesoderm constitutes the tracheoesophageal septum, which separates the esophagus and trachea (2–4). The separation of alimentary and respiratory structures is not always completed successfully. Defective or incomplete separation is one of the most frequent congenital anomalies (2). At 28–30 days, the lung buds continue to elongate, forming the primary bronchi, which develop monopodial outgrowths that lengthen into the segmental bronchi. At the same time, the tissue vascular supply shifts from the splenic plexus to the definite pulmonary arteries (3,4).

The life of a human lung can be subdivided into five distinct phases: embryonic, pseudoglandular, canalicular, saccular, and alveolar. The embryonic period, during which the lung primordium is laid down as a diverticulum of the foregut, lasts about 7 weeks. From the 5th to the 17th week, the lung looks much like a tubuloacinar gland, with epithelial tubes sprouting and branching into the surrounding mesenchyme. In the last week of this pseudoglandular stage, the prospective conductive airways have been formed and the acinar limits can be recognized. The events of the subsequent canalicular phase (weeks 17–26) can be summarized as the widening of the peripheral tubules, differentiation of the cuboidal epithelium into type I and type II cells, formation of the first thin air-blood barriers, and start of surfactant production. During the saccular stage, which follows and lasts until birth, the growth of the pulmonary parenchyma, thinning of the connective tissue between the airspaces, and further maturation of the surfactant system are the most important steps toward independent life. At birth, although already functional, the lung is structurally still in an immature condition, because alveoli, the gas exchange units of the adult lung, are practically missing. The airspaces present are smooth-walled transitory ducts and saccules with primitive type septa that are thick and contain a double capillary network. During the first 1–3 years of postnatal life, alveoli are formed through a septation process that greatly increases the gas exchange surface area. The primitive septa with their capillaries undergo a complete remodeling, gaining the mature slender morphology found in the adult lung (5).

The right lung grows faster than the left, being both larger and having more generations of bronchial branching. At approximately 10 weeks, cartilage appears in the trachea and primary bronchi and at 16 weeks in the segmental bronchi (2,5). At this time, all nonrespiratory airway branches are present and the bronchial branches are widely separated by mesenchyme (1). Up to 16 weeks, during the "glandular stage," the pulmonary mesenchyme is solid and the distal portions of the developing bronchial tree show little or no evidence of lumen. At 24 weeks, during the "alveolar stage," the distal ends of the ducts open and the alveoli are formed (6). The peripheral respiratory epithelium begins to differentiate into type 1 and type 2 pneumocytes at approximately 23–24 weeks gestation (type 2 pneumocytes produce surfactant) (1,6). After 24 weeks, there is an apparent decrease in the number of generations of bronchi due to epithelial changes in terminal bronchioles and their conversion into respiratory bronchioles (5). After 28 weeks of gestation, there is a marked decrease in mesenchymal tissue, the distal airway saccules subdivide, and their walls become thinner. Alveoli first appear at approximately 32 weeks gestation and are usually present by 36 weeks. Alveoli continue to multiply until 300 million have formed. This number is reached when the child is about 8 years old. Alveolar size continues to increase until the adult thoracic cavity configuration is attained. Between 16 and 28 weeks, development and vascularization of the acinus occur. The pulmonary artery develops from the sixth aortic arch and gives off branches that parallel the development of the airways (preacinar vessels) and the alveoli (intraacinar vessels). By the end of the 16th week, the preacinar vessels are formed and supply the capillary bed of the respiratory tissue. Most of the growth and development of intraacinar vessels occurs after birth and follows the rate of alveolar development (5,7).

In the embryonic stage, a diffuse vascular plexus develops in the mesenchyme and divides into pulmonary and esophageal components. This plexus forms a capillary network that fuses with the pulmonary arterial branches during the late embryonic stage and gives rise to the pulmonary venous system. Ultimately, an outpouching of the sinoatrial region of the heart (common pulmonary vein) connects with this venous plexus. The common pulmonary vein becomes incorporated into the many pulmonary veins that drain into the left atrium (1).

Classification of the congenital anomalies of the tracheobronchopulmonary apparatus is difficult and controversial, not only from an embryologic and morphologic standpoint but from a pathologic and clinic viewpoint (2).

	Tracheobronchial Anomalies

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 
Tracheomalacia
Tracheomalacia is defined as tracheal wall softening due to an abnormality of the cartilaginous ring and hypotonia of the myoelastic elements. Tracheomalacia exists when the cartilaginous framework of the trachea is unable to maintain airway patency. The cartilage in the airway of infants is normally soft, and therefore all infants have some degree of dynamic collapse during expiration, when the pressure outside the trachea exceeds the pressure inside. In tracheomalacia, dynamic collapse leads to airway obstruction (14,15). Primary tracheomalacia is thought to be caused by congenital immaturity of the tracheal cartilage. In secondary tracheomalacia, previously normal cartilage undergoes degeneration (14). The congenital variety may be associated with other developmental defects such as a vascular ring or tracheoesophageal fistula (Fig 1) (16,17). All types of tracheomalacia are rare; to our knowledge, no definite prevalence rates are available. The condition may on occasion be symptomatic. The symptoms and treatment are similar to those of asthma.

View larger version (112K): [in this window] [in a new window] [Download PPT slide]   Figure 1a.  Tracheomalacia. (a) Radiograph of the trachea in a 2-month-old infant with stridor shows marked diffuse tracheal narrowing during expiration (arrows). (b, c) Radiographs of a 3-week-old infant with Hurler disease. The trachea (arrows) was noted to be persistently narrowed in all studies.

View larger version (83K): [in this window] [in a new window] [Download PPT slide]   Figure 1b.  Tracheomalacia. (a) Radiograph of the trachea in a 2-month-old infant with stridor shows marked diffuse tracheal narrowing during expiration (arrows). (b, c) Radiographs of a 3-week-old infant with Hurler disease. The trachea (arrows) was noted to be persistently narrowed in all studies.

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 1c.  Tracheomalacia. (a) Radiograph of the trachea in a 2-month-old infant with stridor shows marked diffuse tracheal narrowing during expiration (arrows). (b, c) Radiographs of a 3-week-old infant with Hurler disease. The trachea (arrows) was noted to be persistently narrowed in all studies.

Tracheal Stenosis
Congenital tracheal stenosis is a rare disorder characterized by the presence of focal or diffuse complete tracheal cartilage rings, resulting in a fixed tracheal narrowing. The entity may be seen in isolation or in conjunction with other anomalies, the most common of which is the pulmonary artery sling complex (8–10). Pulmonary artery sling is a rare congenital anomaly in which the left pulmonary artery originates from the right pulmonary artery and encircles the right mainstem bronchus and distal trachea, causing compression of each (8–10). One must be aware of this anomaly when examining an infant with apparent segmental distal tracheal stenosis. A variety of congenital stenosis patterns have been described, along with a variety of different surgical approaches. Approximately 50% of congenital tracheal stenoses are focal, 30% generalized, and 20% funnel-shaped (11). Focal congenital tracheal stenosis consists of a simple local narrowing of the trachea, usually in the lower third. The distal end of the trachea and bronchi are of normal size. Symptoms are variable, depending on the age of the child, the degree of stenosis, and the potential presence of associated anomalies. Infants in whom this disorder is discovered early in life tend to have a worse prognosis (12). Ninety percent of children present during the 1st year of life, often with biphasic stridor. Length of stenosis does not appear to be as critical as degree of stenosis in producing symptoms, as airway resistance is only linearly proportional to length of stenosis, whereas resistance increases fourfold relative to luminal radius decrease. Determining the cause of fixed intrinsic tracheal narrowing in a symptomatic child is crucial. Frontal and lateral high-kilovoltage filtered radiographs are easily obtained and advantageously show the entire airway (9,11) (Fig 2). Because of ionizing radiation, CT should be used only in selected cases.

View larger version (80K): [in this window] [in a new window] [Download PPT slide]   Figure 2a.  Tracheal stenosis. (a) Posteroanterior and (b) lateral radiographs of the upper airways show narrowing of the tracheal lumen in the subglottic trachea (arrows). (c) Curvilinear coronal reformation of CT scan shows the narrowed segment (arrows) (1 = craniocaudal length of the stenosis, 2 = transverse diameter of the tracheal lumen at the stenosis). (d) Posteroanterior radiograph of the trachea in another patient, obtained with filtered high-kilovoltage technique, shows two tracheal narrowings (arrows).

View larger version (108K): [in this window] [in a new window] [Download PPT slide]   Figure 2b.  Tracheal stenosis. (a) Posteroanterior and (b) lateral radiographs of the upper airways show narrowing of the tracheal lumen in the subglottic trachea (arrows). (c) Curvilinear coronal reformation of CT scan shows the narrowed segment (arrows) (1 = craniocaudal length of the stenosis, 2 = transverse diameter of the tracheal lumen at the stenosis). (d) Posteroanterior radiograph of the trachea in another patient, obtained with filtered high-kilovoltage technique, shows two tracheal narrowings (arrows).

View larger version (97K): [in this window] [in a new window] [Download PPT slide]   Figure 2c.  Tracheal stenosis. (a) Posteroanterior and (b) lateral radiographs of the upper airways show narrowing of the tracheal lumen in the subglottic trachea (arrows). (c) Curvilinear coronal reformation of CT scan shows the narrowed segment (arrows) (1 = craniocaudal length of the stenosis, 2 = transverse diameter of the tracheal lumen at the stenosis). (d) Posteroanterior radiograph of the trachea in another patient, obtained with filtered high-kilovoltage technique, shows two tracheal narrowings (arrows).

View larger version (126K): [in this window] [in a new window] [Download PPT slide]   Figure 2d.  Tracheal stenosis. (a) Posteroanterior and (b) lateral radiographs of the upper airways show narrowing of the tracheal lumen in the subglottic trachea (arrows). (c) Curvilinear coronal reformation of CT scan shows the narrowed segment (arrows) (1 = craniocaudal length of the stenosis, 2 = transverse diameter of the tracheal lumen at the stenosis). (d) Posteroanterior radiograph of the trachea in another patient, obtained with filtered high-kilovoltage technique, shows two tracheal narrowings (arrows).

Tracheal Bronchus
Tracheal bronchus was described by Sandifort in 1785 as a right upper bronchus originating in the trachea (3). The term tracheal bronchus includes a variety of bronchial anomalies arising in the trachea or main bronchus and directed toward the upper-lobe territory. This anomalous bronchus usually exits the right lateral wall of the trachea less than 2 cm above the major carina and can supply the entire upper lobe or its apical segment (3,18–20). Tracheal bronchus may be displaced or supernumerary (Fig 3a). If the anatomic upper-lobe bronchus is missing a single branch, the tracheal bronchus is defined as displaced; if the right upper-lobe bronchus has a normal trifurcation into apical, posterior, and anterior segmental bronchi, the tracheal bronchus is defined as supernumerary (1–3,19). The supernumerary bronchi may end blindly; in that case, they are also called tracheal diverticula. If they end in aerated or bronchiectatic lung tissue, they are termed apical accessory lungs or tracheal lobes (2,19,20). Right tracheal bronchus has a prevalence of 0.1%–2% and left tracheal bronchus a prevalence of 0.3%–1% in bronchographic and bronchoscopic studies (3,21). Patients are usually asymptomatic, but the diagnosis of tracheal bronchus should be considered in cases of persistent or recurrent upper-lobe pneumonia, atelectasis or air trapping, and chronic bronchitis. Bronchiectasis, focal emphysema, and cystic lung malformations may coexist (3,18,21). The prevalence of tracheal bronchus in association with infantile lobar emphysema is unknown, but the association is more frequent with left tracheal bronchus (22). Diagnosis of this entity should be considered early in the clinical course of intubated patients with right-upper-lobe complications (18,20,22). Tumoral lesions developing in a tracheal bronchus are infrequent; a few cases have been reported in the English language literature (20). Most of these bronchial branching anomalies are well diagnosed at chest CT as a small area of hypoattenuation arising directly from the trachea (3,20,23) (Fig 3b, 3c).

View larger version (85K): [in this window] [in a new window] [Download PPT slide]   Figure 3a.  Tracheal bronchus. (a) Drawing shows the most frequent origin of the tracheal bronchus (arrows). (b) CT section demonstrates a right-upper-lobe bronchus (arrows) arising from the trachea, above the carina. (c) CT scan of the same patient at the level of the carina, 2 cm below the origin of the tracheal bronchus. (d) Bronchogram helps confirm the diagnosis and shows the origin of the tracheal bronchus. Rib alterations in the right hemithorax are secondary to prior thoracotomy.

View larger version (64K): [in this window] [in a new window] [Download PPT slide]   Figure 3b.  Tracheal bronchus. (a) Drawing shows the most frequent origin of the tracheal bronchus (arrows). (b) CT section demonstrates a right-upper-lobe bronchus (arrows) arising from the trachea, above the carina. (c) CT scan of the same patient at the level of the carina, 2 cm below the origin of the tracheal bronchus. (d) Bronchogram helps confirm the diagnosis and shows the origin of the tracheal bronchus. Rib alterations in the right hemithorax are secondary to prior thoracotomy.

View larger version (66K): [in this window] [in a new window] [Download PPT slide]   Figure 3c.  Tracheal bronchus. (a) Drawing shows the most frequent origin of the tracheal bronchus (arrows). (b) CT section demonstrates a right-upper-lobe bronchus (arrows) arising from the trachea, above the carina. (c) CT scan of the same patient at the level of the carina, 2 cm below the origin of the tracheal bronchus. (d) Bronchogram helps confirm the diagnosis and shows the origin of the tracheal bronchus. Rib alterations in the right hemithorax are secondary to prior thoracotomy.

View larger version (152K): [in this window] [in a new window] [Download PPT slide]   Figure 3d.  Tracheal bronchus. (a) Drawing shows the most frequent origin of the tracheal bronchus (arrows). (b) CT section demonstrates a right-upper-lobe bronchus (arrows) arising from the trachea, above the carina. (c) CT scan of the same patient at the level of the carina, 2 cm below the origin of the tracheal bronchus. (d) Bronchogram helps confirm the diagnosis and shows the origin of the tracheal bronchus. Rib alterations in the right hemithorax are secondary to prior thoracotomy.

Most patients with tracheal bronchus can be treated conservatively; however, in symptomatic patients surgical excision of the involved segment is necessary (24).

Bronchial Atresia
Congenital bronchial atresia is a rare anomaly that results from focal obliteration of a proximal segmental or subsegmental bronchus that lacks communication with the central airways. The development of distal structures is normal (1,25,26). Bronchial atresia most often affects segmental bronchi at or near their origin; however, lobar or subsegmental bronchi may also be involved. The bronchi distal to the stenosis become filled with mucus and form a bronchocele. The alveoli supplied by these bronchi are ventilated by collateral pathways and show features of air-trapping, resulting in a region of hyperinflation around the dilated bronchi (25,27). In some cases, bronchial atresia may be acquired postnatally owing to traumatic or postinflammatory insult to the bronchus (1). The upper-lobe bronchi are more frequently affected; middle and lower lobes are rarely affected (25). The abnormality is an incidental finding in approximately 50% of cases, mostly in young men, and generally produces no symptoms or signs.

In the newborn period, bronchial atresia is seen as a water-density mass. The mass is fetal lung liquid trapped behind the atresia. Later in childhood, the fetal lung liquid escapes and bronchial atresia is found because of focal air trapping. The short atretic segment leads to accumulation of mucus within the distal bronchi to form a bronchocele, and underventilation of the affected part of the lung occurs. In adults, bronchial atresia characteristically is seen as a solitary pulmonary nodule due to a mucus plug and less frequently as congenital lobar emphysema (25). Bronchial atresia is usually asymptomatic and is found incidentally in chest radiographs; however, dyspnea, pneumonia, and bronchial asthma have been reported (25). The characteristic chest radiographic finding consists of a bronchocele, seen as rounded, branching opacities radiating from the hilum. The bronchocele may contain an air-fluid level. The distal lung is emphysematous and produces an area of hyperlucency around the affected bronchi. In newborns, the affected segment may be seen as a fluid-filled mass (25). CT is a sensitive modality for demonstrating the typical features of bronchial atresia. It shows a round opacity at the site of the atresia, medial to the air trapping, which can be clearly depicted by performing expiratory CT (28) (Fig 4).

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 4a.  Bronchial atresia (a) CT scan shows air trapping in the right upper lobe (arrows). (b) CT scan in the same patient shows a round opacity at the site of the atresia, medial to the air trapping, representing mucoid impaction just distal to the atresia.

View larger version (107K): [in this window] [in a new window] [Download PPT slide]   Figure 4b.  Bronchial atresia (a) CT scan shows air trapping in the right upper lobe (arrows). (b) CT scan in the same patient shows a round opacity at the site of the atresia, medial to the air trapping, representing mucoid impaction just distal to the atresia.

Bronchogenic Cyst
Bronchopulmonary foregut malformations are anomalies of pulmonary development that are due to abnormal budding of the embryonic foregut and tracheobronchial tree. This abnormality includes foregut cysts, bronchogenic cysts, enteric cysts, and neuroenteric cysts (29–31).

Bronchogenic cysts are congenital lesions thought to originate from the primitive ventral foregut and may be mediastinal, intrapulmonary, or, less frequently, in the lower neck. Approximately two-thirds are within the mediastinum, and one-third are intraparenchymal (29,32,33). They account for 40%–50% of all congenital mediastinal (intrathoracic) cysts, and there is a slight male predominance. The frequency of bronchogenic cysts is unknown presumably because most patients are asymptomatic. Numerous studies have documented the rare frequency of bronchogenic cysts, with an average incidence of 20 cases over a 20-year period. The cysts contain mucoid material and are lined by ciliated columnar or cuboidal epithelium. Their walls contain smooth muscle and often cartilage. They are sometimes intrapulmonary, typically in the medial third of the lung. If in a mediastinal location, they may be paratracheal (usually right-sided), carinal, or hilar. The carinal location is most frequent. They also can be found in the posterior and anterior mediastinum (in the latter location, it may be necessary to distinguish them from other more frequent anterior mediastinal cysts such as cystic teratoma, thymic cysts, or cysts derived from ectopic thyroids glands) (31,33).

Bronchogenic cysts do not initially communicate with the tracheobronchial tree. Instrumentation of the cyst or infection may lead to air-filled cyst or an air-fluid level. Two-thirds of the patients are symptomatic; symptoms are due to the size and position of the cyst. Symptoms are most frequently caused by compression of the trachea or bronchi, which leads to cough, wheezing, stridor, dyspnea, cyanotic spells, and pneumonia. Infection occurs in 20% of patients with intraparenchymal cysts, usually secondary to communication with the tracheobronchial tree (34). However, most bronchogenic cysts in children are found incidentally when imaging is performed for other reasons

Bronchogenic cysts are rarely detected with prenatal sonography. To our knowledge, the first case reported in the medical literature was by Avni et al in 1986 (35). They usually seen as a unilocular, fluid-filled cyst in the middle or posterior mediastinum. Differential considerations include esophageal duplication cyst, neuroenteric cyst and congenital cystic adenomatoid malformation (36). Intrapulmonary bronchogenic cysts are usually located in the lower lobes (37). In infants and children, the chest radiograph is diagnostic for bronchogenic cysts in three out of four cases (32). The cysts are filled with serous or mucous fluid, so usually appear as water-density mass lesions in chest radiographs (Fig 5).

View larger version (156K): [in this window] [in a new window] [Download PPT slide]   Figure 5a.  Bronchogenic cyst. (a) Chest radiograph of an asymptomatic 5-year-old girl shows a large soft-tissue mass in the right hemithorax (arrows). (b) Contrast material-enhanced CT scan through the upper lobes shows a well-defined water-density homogeneous mass (*) with no contrast enhancement.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 5b.  Bronchogenic cyst. (a) Chest radiograph of an asymptomatic 5-year-old girl shows a large soft-tissue mass in the right hemithorax (arrows). (b) Contrast material-enhanced CT scan through the upper lobes shows a well-defined water-density homogeneous mass (*) with no contrast enhancement.

View larger version (134K): [in this window] [in a new window] [Download PPT slide]   Figure 6a.  Complicated bronchogenic cyst. (a) Chest radiograph shows rounded mass with an air-fluid level, occupying the entire right middle lobe, corresponding to a bronchogenic cyst connecting with the bronchus. (b) Contrast-enhanced CT scan shows a thick-walled fluid-filled rounded mass (*) with an air-fluid level, corresponding to the infected bronchogenic cyst. Note enhancement of the cystic wall.

View larger version (120K): [in this window] [in a new window] [Download PPT slide]   Figure 6b.  Complicated bronchogenic cyst. (a) Chest radiograph shows rounded mass with an air-fluid level, occupying the entire right middle lobe, corresponding to a bronchogenic cyst connecting with the bronchus. (b) Contrast-enhanced CT scan shows a thick-walled fluid-filled rounded mass (*) with an air-fluid level, corresponding to the infected bronchogenic cyst. Note enhancement of the cystic wall.

T1-weighted MR images show that the intrinsic signal intensity ranges from low to high depending on cyst contents. On T2-weighted MR images, the cysts are typically high in signal intensity (29,36). The possibility of malignancy should be considered when a solid component is seen in a cyst wall at CT or MR imaging (33).

	Anomalies of the Lung

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 
Pulmonary Underdevelopment
Pulmonary underdevelopment has been classified into three groups by Schneider and Schwalbe (40). In group 1, bronchus and lung are absent (agenesis); in group 2, a rudimentary bronchus is present and limited to a blind-end pouch without lung tissue (aplasia); and in group 3, there is bronchial hypoplasia with variable reduction of lung tissue (hypoplasia) (1,28).

Pulmonary agenesis occurs during the embryogenic period (approximately 4 weeks gestation), when the primitive lung is forming. The etiology of lung agenesis is unknown, although genetic, teratogenic, and mechanical factors have been proposed as possible causes. The abnormality is usually unilateral, and there is no side or gender predominance (40,41). More than 50% of children with pulmonary agenesis have associated congenital anomalies that involve the cardiovascular (more frequent patent ductus arteriosus and patent foramen ovale), gastrointestinal, skeletal, and genitourinary systems. Most of the limb and spinal anomalies are ipsilateral to the pulmonary agenesis, whereas the rib anomalies are variable. The contralateral lung is normal in structure but has compensatory hypertrophy. Patients with right-lung agenesis have a shorter life expentancy than those with left-lung agenesis; this suggests that the right-lung agenesis has a greater frequency of an associated shift of the heart and mediastinum, with corresponding distortion of bloods vessel and bronchi (37,38). The diagnosis of lung agenesis is usually first suspected at chest radiography that demonstrates a small, completely opaque hemithorax with displacement of the mediastinal structures and diaphragm (Fig 7).

View larger version (88K): [in this window] [in a new window] [Download PPT slide]   Figure 7a.  Lung agenesis. (a) Schematic of lung agenesis. (b) Posteroanterior and (c) lateral radiographs of a 5-year-old boy with complete opacity of the right hemithorax and displacement of the heart and mediastinum to the right. Note the tracheal displacement to the right. (d) Bronchography and (e) pulmonary angiography in the same patient demonstrate complete absence of the main right pulmonary bronchus and artery, with normal left arteries and bronchial branches

View larger version (165K): [in this window] [in a new window] [Download PPT slide]   Figure 7b.  Lung agenesis. (a) Schematic of lung agenesis. (b) Posteroanterior and (c) lateral radiographs of a 5-year-old boy with complete opacity of the right hemithorax and displacement of the heart and mediastinum to the right. Note the tracheal displacement to the right. (d) Bronchography and (e) pulmonary angiography in the same patient demonstrate complete absence of the main right pulmonary bronchus and artery, with normal left arteries and bronchial branches

View larger version (136K): [in this window] [in a new window] [Download PPT slide]   Figure 7c.  Lung agenesis. (a) Schematic of lung agenesis. (b) Posteroanterior and (c) lateral radiographs of a 5-year-old boy with complete opacity of the right hemithorax and displacement of the heart and mediastinum to the right. Note the tracheal displacement to the right. (d) Bronchography and (e) pulmonary angiography in the same patient demonstrate complete absence of the main right pulmonary bronchus and artery, with normal left arteries and bronchial branches

View larger version (175K): [in this window] [in a new window] [Download PPT slide]   Figure 7d.  Lung agenesis. (a) Schematic of lung agenesis. (b) Posteroanterior and (c) lateral radiographs of a 5-year-old boy with complete opacity of the right hemithorax and displacement of the heart and mediastinum to the right. Note the tracheal displacement to the right. (d) Bronchography and (e) pulmonary angiography in the same patient demonstrate complete absence of the main right pulmonary bronchus and artery, with normal left arteries and bronchial branches

View larger version (112K): [in this window] [in a new window] [Download PPT slide]   Figure 7e.  Lung agenesis. (a) Schematic of lung agenesis. (b) Posteroanterior and (c) lateral radiographs of a 5-year-old boy with complete opacity of the right hemithorax and displacement of the heart and mediastinum to the right. Note the tracheal displacement to the right. (d) Bronchography and (e) pulmonary angiography in the same patient demonstrate complete absence of the main right pulmonary bronchus and artery, with normal left arteries and bronchial branches

View larger version (166K): [in this window] [in a new window] [Download PPT slide]   Figure 8a.  Lung agenesis of the left upper lobe. (a) Posteroanterior and (b) lateral chest radiographs of a girl with opacity of the left upper lobe (white arrows) and displacement of the mediastinum to the left. Note the compensatory hyperinflation of the left lower lobe. There are various hemivertebra (black arrows) and small left ribs.

View larger version (136K): [in this window] [in a new window] [Download PPT slide]   Figure 8b.  Lung agenesis of the left upper lobe. (a) Posteroanterior and (b) lateral chest radiographs of a girl with opacity of the left upper lobe (white arrows) and displacement of the mediastinum to the left. Note the compensatory hyperinflation of the left lower lobe. There are various hemivertebra (black arrows) and small left ribs.

Pulmonary hypoplasia is defined as deficient or incomplete development of the lungs (39). It is characterized by the presence of both bronchi and alveoli in an underdeveloped lobe, and it is caused by factors directly or indirectly compromising the thoracic space available for lung growth (40), such as a congenital diaphragmatic hernia in which a defect of the hemidiaphragma allows the abdominal viscera to herniate into the thoracic cavity with compression of the ipsilateral lung. Pulmonary hypoplasia also is noted in extralobar sequestration, agenesis of the diaphragm, large pleural effusion, and Jeune syndrome (asphyxiating thoracic dystrophy), a rare entity in which a small and rigid thoracic cage produces a decrease in lung volume. The extrathoracic causes include oligohydramnios (Potter syndrome: renal agenesis, abnormal fasciae, limb anomalies, and bilateral pulmonary hypoplasia), in which the mechanism of development is unknown but is thought to be predominantly compression of the fetal thorax by the uterus. Other causes include decreased pulmonary vascular perfusion (tetralogy of Fallot, unilateral absence of the pulmonary artery). Intrathoracic causes, such as a congenital diaphragmatic hernia, are the most common (1,39). The true prevalence is unknown, but in cases of premature rupture of membranes at 15–28 weeks gestation, the reported prevalence of pulmonary hypoplasia ranges from 9% to 28%.

The most common manifestation is early respiratory distress after birth, cyanosis, tachypnea, hypoxia, hypercapnea, and acidosis. Pneumothorax and pulmonary hypertension are common serious complications. Pneumothorax often develops spontaneously or secondary to mechanical ventilation. The degree of pulmonary hypoplasia depends on the volume and duration of the cause. Plain radiographs demonstrate decreased aeration of the affected hemithorax (more frequent in the right lung) and a small thoracic cage (Fig 9).

View larger version (99K): [in this window] [in a new window] [Download PPT slide]   Figure 9a.  Pulmonary hypoplasia. (a) Schematic illustrates pulmonary hypoplasia. (b) Anteroposterior chest radiograph of a 7-month-old infant shows opacity of the left hemithorax and small left lung (arrows) with ipsilateral displacement of the mediastinum, secondary to repaired Bochdaleck hernia.

View larger version (127K): [in this window] [in a new window] [Download PPT slide]   Figure 9b.  Pulmonary hypoplasia. (a) Schematic illustrates pulmonary hypoplasia. (b) Anteroposterior chest radiograph of a 7-month-old infant shows opacity of the left hemithorax and small left lung (arrows) with ipsilateral displacement of the mediastinum, secondary to repaired Bochdaleck hernia.

View larger version (154K): [in this window] [in a new window] [Download PPT slide]   Figure 10a.  Pulmonary hypoplasia. (a) Anteroposterior radiograph shows opacity of the right hemithorax and a shift of the mediastinal structures to the right, due to pulmonary hypoplasia secondary to right diaphragmatic agenesis. (b) Angiographic MR image of a 10-year-old boy shows a hypoplastic right pulmonary artery (arrows).

View larger version (156K): [in this window] [in a new window] [Download PPT slide]   Figure 10b.  Pulmonary hypoplasia. (a) Anteroposterior radiograph shows opacity of the right hemithorax and a shift of the mediastinal structures to the right, due to pulmonary hypoplasia secondary to right diaphragmatic agenesis. (b) Angiographic MR image of a 10-year-old boy shows a hypoplastic right pulmonary artery (arrows).

View larger version (81K): [in this window] [in a new window] [Download PPT slide]   Figure 11a.  Scimitar syndrome. (a) Schematic illustrates the characteristic findings of the scimitar syndrome. (b) Chest radiograph shows decreased aeration of the right hemithorax and displacement of the heart and mediastinum to the right. There is loss of the right heart shadow due to the right pulmonary hypoplasia and to the pulmonary vein coursing to the right cardiophrenic angle (scimitar sign) (arrows). (c) Angiographic MR image shows the anomalous vein draining into the inferior vena cava (arrows). (d) Angiographic MR image of a patient after surgery for scimitar syndrome. Note the anomalous vein draining now into the right atrium (arrow).

View larger version (156K): [in this window] [in a new window] [Download PPT slide]   Figure 11b.  Scimitar syndrome. (a) Schematic illustrates the characteristic findings of the scimitar syndrome. (b) Chest radiograph shows decreased aeration of the right hemithorax and displacement of the heart and mediastinum to the right. There is loss of the right heart shadow due to the right pulmonary hypoplasia and to the pulmonary vein coursing to the right cardiophrenic angle (scimitar sign) (arrows). (c) Angiographic MR image shows the anomalous vein draining into the inferior vena cava (arrows). (d) Angiographic MR image of a patient after surgery for scimitar syndrome. Note the anomalous vein draining now into the right atrium (arrow).

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 11c.  Scimitar syndrome. (a) Schematic illustrates the characteristic findings of the scimitar syndrome. (b) Chest radiograph shows decreased aeration of the right hemithorax and displacement of the heart and mediastinum to the right. There is loss of the right heart shadow due to the right pulmonary hypoplasia and to the pulmonary vein coursing to the right cardiophrenic angle (scimitar sign) (arrows). (c) Angiographic MR image shows the anomalous vein draining into the inferior vena cava (arrows). (d) Angiographic MR image of a patient after surgery for scimitar syndrome. Note the anomalous vein draining now into the right atrium (arrow).

View larger version (147K): [in this window] [in a new window] [Download PPT slide]   Figure 11d.  Scimitar syndrome. (a) Schematic illustrates the characteristic findings of the scimitar syndrome. (b) Chest radiograph shows decreased aeration of the right hemithorax and displacement of the heart and mediastinum to the right. There is loss of the right heart shadow due to the right pulmonary hypoplasia and to the pulmonary vein coursing to the right cardiophrenic angle (scimitar sign) (arrows). (c) Angiographic MR image shows the anomalous vein draining into the inferior vena cava (arrows). (d) Angiographic MR image of a patient after surgery for scimitar syndrome. Note the anomalous vein draining now into the right atrium (arrow).

The clinical significance and prognosis of scimitar sydrome depend to a large extent on the amount of the resulting left-right shunt; at least 40% of patients are asymptomatic. This syndrome may be discovered when patients undergo routine chest radiography. The clinical symptoms usually manifest in the 2nd to 3rd decade of life, with fatigue and dyspnea with exertion being most common and recurrent pulmonary infection less common (1). In the infantile group, a higher prevalence of pulmonary hypertension has been reported (44). The diagnosis is based on chest radiography, ultrasonography, CT, and MR imaging (43–46). The radiographic appearance of the pulmonary vein descending along the right cardiac border is characteristic (scimitar sign) (1,45) (Fig 11b). The vein may not be visible if it is small or obscured by the heart shadow. The aberrant vein is located posteriorly in lateral chest radiographs. CT may show the size of the right hemithorax, bronchial anomalies, and the anomalous vein. Doppler ultrasonography may show the entrance of the anomalous vein into the inferior vena cava and can verify the venous flow. Angiography may identify the aberrant vein, showing the size of the right pulmonary artery (1). Several reports have described the feasibility of noninvasive techniques, such as cine MR imaging and contrast-enhanced angiographic MR imaging for evaluation of this syndrome (Fig 11c, 11d). This technique offers excellent visualization of pulmonary vascular anatomy (46).

Congenital Cystic Adenomatoid Malformation
Congenital cystic adenomatoid malformation of the lung is an uncommon cause of respiratory distress in neonates and infants. It is characterized by a multicystic mass of pulmonary tissue with an abnormal proliferation of bronchial structures (41). Pathogenetically, congenital cystic adenomatoid malformation has been attributed to an overgrowth of bronchioles, with almost complete suppression of alveolar development between the 7th and 10th weeks of embryonic life (2,47) This malformation was classified by Stoker et al (48) into three histologic types. Type I is composed of variable-size cysts, with at least one dominant cyst (>2 cm in diameter) (Figs 12, 13). This is the most common (75%) form.

View larger version (159K): [in this window] [in a new window] [Download PPT slide]   Figure 12a.  Type I congenital cystic adenomatoid malformation. (a) Anteroposterior and (b) lateral chest radiographs of a newborn show a multicystic mass occupying the right hemithorax (note the variable size of the cysts, some of them >2 cm) (arrows).

View larger version (159K): [in this window] [in a new window] [Download PPT slide]   Figure 12b.  Type I congenital cystic adenomatoid malformation. (a) Anteroposterior and (b) lateral chest radiographs of a newborn show a multicystic mass occupying the right hemithorax (note the variable size of the cysts, some of them >2 cm) (arrows).

View larger version (153K): [in this window] [in a new window] [Download PPT slide]   Figure 13a.  Type I congenital cystic adenomatoid malformation. (a) Anteroposterior chest radiograph of a 5-year-old child shows a bubbly mass in the left upper lobe with a dominant air cyst morre than 4 cm in diameter (arrows). (b) CT scan of the same patient shows a hypoattenuating, clearly delineated cystic mass (*) in the left upper lobe.

View larger version (119K): [in this window] [in a new window] [Download PPT slide]   Figure 13b.  Type I congenital cystic adenomatoid malformation. (a) Anteroposterior chest radiograph of a 5-year-old child shows a bubbly mass in the left upper lobe with a dominant air cyst morre than 4 cm in diameter (arrows). (b) CT scan of the same patient shows a hypoattenuating, clearly delineated cystic mass (*) in the left upper lobe.

View larger version (166K): [in this window] [in a new window] [Download PPT slide]   Figure 14a.  Type II congenital cystic adenomatoid malformation. (a) Anteroposterior chest radiograph of a newborn shows a heterogeneous bubbly mass in the left lung displacing mediastinal structures to the right. (b) Coronal T1-weighted image in the same patient shows cysts (arrows) smaller than 2 cm in diameter. (c) In another newborn patient, chest CT shows a complex cystic mass in the right upper lobe, smaller than the type I mass seen in Figure 13b.

View larger version (184K): [in this window] [in a new window] [Download PPT slide]   Figure 14b.  Type II congenital cystic adenomatoid malformation. (a) Anteroposterior chest radiograph of a newborn shows a heterogeneous bubbly mass in the left lung displacing mediastinal structures to the right. (b) Coronal T1-weighted image in the same patient shows cysts (arrows) smaller than 2 cm in diameter. (c) In another newborn patient, chest CT shows a complex cystic mass in the right upper lobe, smaller than the type I mass seen in Figure 13b.

View larger version (104K): [in this window] [in a new window] [Download PPT slide]   Figure 14c.  Type II congenital cystic adenomatoid malformation. (a) Anteroposterior chest radiograph of a newborn shows a heterogeneous bubbly mass in the left lung displacing mediastinal structures to the right. (b) Coronal T1-weighted image in the same patient shows cysts (arrows) smaller than 2 cm in diameter. (c) In another newborn patient, chest CT shows a complex cystic mass in the right upper lobe, smaller than the type I mass seen in Figure 13b.

View larger version (165K): [in this window] [in a new window] [Download PPT slide]   Figure 15.  Type III congenital cystic adenomatoid malformation. Anteroposterior chest radiograph of a premature girl weighing 700 g shows an irregular microcystic mass affecting the left lung and displacing the mediastinum to the right. There is an associated dextrocardia.

The postnatal diagnosis is made with plain chest radiography, which demonstrates multiple air-filled thin-walled cysts that vary in size. Unlike in diaphragmatic hernia, the distribution of abdominal bowel gas is normal. Air-fluid levels may be seen with or without superimposed infection. In severe cases, the lung may be hyperexpanded, with mediastinal shift, a flat hemidiaphragm, and herniation of the lung to the contralateral side. CT can be useful for characterizing congenital cystic adenomatoid malformation by showing its location and extent (Figs 13b, 14c), and for differentiating it from congenital lobar emphysema and bronchogenic cysts. In older infants and children with recurrent infections, this condition must be differentiated from necrotizing pneumonia. Recurrent infection in the same site, hyperexpansion of the affected lobe, and absence of air bronchograms favor the former diagnosis (49).

Congenital Lobar Emphysema
Congenital lobar emphysema is characterized by progressive overdistention of a lobe, sometimes two lobes. It is thought to result from a check-valve mechanism at the bronchial level that causes progressive hyperinflaction of the lung by allowing more air to enter the involved area on inspiration than leaves on expiration (51–54). The most commonly affected lobe is the left upper lobe, followed by the middle lobe. The distribution of lobar involvement is 42.2% in the left upper lobe, 35.3% in the right middle lobe, 20.7% in the right upper lobe, and 0.9% in each lower lobe (52). There is no destruction of alveolar walls. In 50%–55% of cases, the cause of congenital lobar emphysema is unknown, although areas of malacia or stenosis of the bronchial cartilage were found in these patients and these are considered the most likely explanations (52,53). Congenital lobar emphysema may be associated with other anomalies (cardiovascular system is involved in 12%–14%) (51,52). It is more common among males than females; it is not familial and occurs predominantly in Caucasians. Most patients become symptomatic during the neonatal period, most before 6 months of age (52,53). Myers (59) described three clinical types, classified according to whether congenital lobar emphysema becomes symptomatic in infancy (type I), in older children (type II), or is an incidental finding in asymptomatic patients (type III). Types II and III are rare (51,52). Respiratory distress is the most common symptom at presentation. Diagnosis is obtained by means of chest radiography and CT, which show hyperinflation of the segment or lobe affected (Figs 16, 17).

View larger version (70K): [in this window] [in a new window] [Download PPT slide]   Figure 16a.  Congenital lobar emphysema. (a) Schematic illustrates congenital lobar emphysema. (b) Posteroanterior chest radiograph shows a lucent mass in the right upper lobe (arrows) that displaces mediastinal structures to the left. (c) Lateral view shows a hyperlucent retrosternal area (arrows) that corresponds to the lobar emphysema.

View larger version (163K): [in this window] [in a new window] [Download PPT slide]   Figure 16b.  Congenital lobar emphysema. (a) Schematic illustrates congenital lobar emphysema. (b) Posteroanterior chest radiograph shows a lucent mass in the right upper lobe (arrows) that displaces mediastinal structures to the left. (c) Lateral view shows a hyperlucent retrosternal area (arrows) that corresponds to the lobar emphysema.

View larger version (126K): [in this window] [in a new window] [Download PPT slide]   Figure 16c.  Congenital lobar emphysema. (a) Schematic illustrates congenital lobar emphysema. (b) Posteroanterior chest radiograph shows a lucent mass in the right upper lobe (arrows) that displaces mediastinal structures to the left. (c) Lateral view shows a hyperlucent retrosternal area (arrows) that corresponds to the lobar emphysema.

View larger version (163K): [in this window] [in a new window] [Download PPT slide]   Figure 17a.  Congenital lobar emphysema. (a) One-year-old boy with hyperlucent left lung that herniates to the right (arrow), with displacement of mediastinal structures to the right. (b) CT scan shows hyperinflation of the entire left upper lobe, with patent vascular structures and slight mediastinal shift to the right.

View larger version (82K): [in this window] [in a new window] [Download PPT slide]   Figure 17b.  Congenital lobar emphysema. (a) One-year-old boy with hyperlucent left lung that herniates to the right (arrow), with displacement of mediastinal structures to the right. (b) CT scan shows hyperinflation of the entire left upper lobe, with patent vascular structures and slight mediastinal shift to the right.

Pulmonary Sequestration
Pulmonary sequestration is defined as an aberrant lung tissue mass that has no normal connection with the bronchial tree or with the pulmonary arteries. The arterial blood supply arises from the systemic arteries, usually the thoracic or abdominal aorta, and its venous drainage is via the azygous system, the pulmonary veins, or the inferior vena cava (32,37). Sequestration is divided into two types: extralobar and intrapulmonary (Fig 18).

View larger version (84K): [in this window] [in a new window] [Download PPT slide]   Figure 18a.  Pulmonary sequestration. (a) Schematic illustrates intra- and extralobar sequestration. (b) Frontal chest radiograph shows a water-density mass (arrows) located posteriorly in the left lower lobe. (c) Aortogram of the same patient shows the feeding vessel (arrows) of the sequestration arising from the aorta.

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 18b.  Pulmonary sequestration. (a) Schematic illustrates intra- and extralobar sequestration. (b) Frontal chest radiograph shows a water-density mass (arrows) located posteriorly in the left lower lobe. (c) Aortogram of the same patient shows the feeding vessel (arrows) of the sequestration arising from the aorta.

View larger version (177K): [in this window] [in a new window] [Download PPT slide]   Figure 18c.  Pulmonary sequestration. (a) Schematic illustrates intra- and extralobar sequestration. (b) Frontal chest radiograph shows a water-density mass (arrows) located posteriorly in the left lower lobe. (c) Aortogram of the same patient shows the feeding vessel (arrows) of the sequestration arising from the aorta.

Extralobar sequestration is a mass of abnormal lung tissue that is surrounded by its own separate pleura (32,37). It is usually located in the posterior lower chest, and 90% of extralobar sequestrations are located on the left side (37). It is more common than intralobar sequestration. Extralobar sequestration is associated with diaphragmatic hernia, congenital heart disease, and congenital cystic adenomatoid malformation (55). There is a four to one male to female predominance (32). Both extra- and intralobar sequestration can show patent communication with the foregut, being more frequently reported for the extralobar form (also called congenital bronchopulmonary foregut malformation) (56). The extralobar form is most commonly diagnosed in the prenatal and neonatal periods, whereas the intralobar form is usually diagnosed in childhood.

Sequestration is seen on prenatal sonograms as a hyperechoic mass, usually in the posterior basal hemithorax. Sometimes it is associated with a small cyst. Extralobar sequestration may be seen as an infradiaphragmatic mass. Color Doppler ultrasonography is useful for demostrating anomalous vessels and tracing them to their origin (32,55). Prenatal MR imaging shows a well-defined mass with sharp margins and high signal intensity (41). In neonates and infants, pulmonary sequestration is usually associated with recurrent lower lobe pneumonia. In chest radiographs, it has the appearance of a soft-tissue opacity in the posterior basal segment of the lung, with smooth or lobulated margins (Figs 18, 19). Brochiectasis, subsegmental atelectasis, mediastinal shift, and prominence of the ipsilateral hilum are additional radiographic findings (32,55). CT scans show a soft-tissue cystic mass containing air or fluid, focal emphysema, and a hypervascular focus of lung tissue (Fig 19b).

View larger version (142K): [in this window] [in a new window] [Download PPT slide]   Figure 19a.  Pulmonary sequestration. (a) Anteroposterior chest radiograph demonstrates a mass located posteriorly in the right lower lobe (arrows). (b) CT scan of same patient shows a complex mass affecting the medial basilar segment of the right lower lobe (arrow).

View larger version (104K): [in this window] [in a new window] [Download PPT slide]   Figure 19b.  Pulmonary sequestration. (a) Anteroposterior chest radiograph demonstrates a mass located posteriorly in the right lower lobe (arrows). (b) CT scan of same patient shows a complex mass affecting the medial basilar segment of the right lower lobe (arrow).

	Esophageal Anomalies

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 
Esophageal Atresia and Tracheoesophageal Fistula
Esophageal atresia, with or without tracheoesophageal fistula, is the most common congenital malformation of the esophagus. Esophageal atresia and tracheoesophageal fistula represent a complex of congenital anomalies characterized by a failure of formation of the tubular esophagus and/or an abnormal communication between the esophagus and trachea. The precise cause is unknown, but it is thought to be due to a developmental disorder in formation and separation of the primitive foregut into trachea and esophagus (57). In early fetal life, the esophagus and trachea are one tube, which divides into two structures by the folding in of the lateral walls of the foregut. If the folding process is incomplete and the lateral mesodermal walls fail to meet at any point, tracheoesophageal fistula results. If these lateral folds turn dorsally in their development, thereby cutting through the esophageal lumen, atresia results. However, intrauterine anoxia or stress with resulting vascular compromise may produce focal necrosis of the esophagus with resulting atresia or tracheoesophageal communication (58). In 25% of cases, the anomaly is associated with other gastrointestinal malformations such as imperforate anus, pyloric stenosis, duodenal atresia, annular pancreas, and, less frequently, with cardiac, genitourinary, and vertebral changes (59). The "VACTERL" complex (vertebral, anal, cardiovascular, tracheoesophageal, renal, radial, and limb malformations) is perhaps the best known group of anomalies associated with tracheoesophageal lesions (60,61). Different types of atresia are recognized depending on the presence or absence of tracheoesophageal fistula and its location (59,62) (Figs 20, 21). Type A (Fig 20) corresponds to pure esophageal atresia without fistula, type B is esophageal atresia with fistula between the proximal pouch and the trachea, type C is esophageal atresia and fistula from the trachea or the main bronchus to the distal esophageal segment, type D is esophageal atresia with both proximal and distal fistulas, and type E is tracheoesophageal fistula without atresia. Type C is by far the most common. Esophageal atresia is generally suspected on the basis of polyhydramnios, inability to swallow saliva or milk, aspiration during early feedings, or failure to successfully pass a catheter into the stomach. Feeding difficulties with choking occur in infants with type E (fistula without atresia), but the diagnosis may be delayed for years even with the presentation of cough when swallowing, recurrent pneumonia, and distended abdomen (63,64).

View larger version (35K): [in this window] [in a new window] [Download PPT slide]   Figure 20.  Schematic illustrates esophageal atresia and traacheoesophageal fistula. A, Atresia without fistula; B, atresia with proximal fistula; C, atresia with distal fistula; D, atresia with both distal and proximal fistulas; E, H-shaped fistula without atresia. The plain radiographs for types A and B are similar, as is the case for types C and D. (Reproduced, with permission, from reference 59)

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 21a.  Esophageal atresia. (a) Esophageal atresia without fistula (type A). Frontal projection shows absence of air in the gastrointestinal tract; therefore, there is no distal traacheoesophageal fistula. This image is similar to that for atresia with proximal fistula (type B). (b) Esophageal atresia with distal fistula (type C). The catheter is coiled within the upper esophageal pouch (arrows). Air is also present in the gastrointestinal tract, indicating communication between the distal esophageal segment and the respiratory tree. (c) Tracheoesophageal fistula without atresia (type E). The fistula (arrow) arises from the anterior portion of the esophagus and passes cephalad to the posterior portion of the trachea.

View larger version (155K): [in this window] [in a new window] [Download PPT slide]   Figure 21b.  Esophageal atresia. (a) Esophageal atresia without fistula (type A). Frontal projection shows absence of air in the gastrointestinal tract; therefore, there is no distal traacheoesophageal fistula. This image is similar to that for atresia with proximal fistula (type B). (b) Esophageal atresia with distal fistula (type C). The catheter is coiled within the upper esophageal pouch (arrows). Air is also present in the gastrointestinal tract, indicating communication between the distal esophageal segment and the respiratory tree. (c) Tracheoesophageal fistula without atresia (type E). The fistula (arrow) arises from the anterior portion of the esophagus and passes cephalad to the posterior portion of the trachea.

View larger version (87K): [in this window] [in a new window] [Download PPT slide]   Figure 21c.  Esophageal atresia. (a) Esophageal atresia without fistula (type A). Frontal projection shows absence of air in the gastrointestinal tract; therefore, there is no distal traacheoesophageal fistula. This image is similar to that for atresia with proximal fistula (type B). (b) Esophageal atresia with distal fistula (type C). The catheter is coiled within the upper esophageal pouch (arrows). Air is also present in the gastrointestinal tract, indicating communication between the distal esophageal segment and the respiratory tree. (c) Tracheoesophageal fistula without atresia (type E). The fistula (arrow) arises from the anterior portion of the esophagus and passes cephalad to the posterior portion of the trachea.

Esophageal Duplications
Duplications of the esophagus are the second most common duplications of the gastrointestinal tract after those of the ileum, comprising 15%–20% of all those reported (67–69). Several theories have been proposed to explain the embryologic basis for gastrointestinal tract duplications. No single hypothesis, however, can explain all duplications in all locations and all of their associated anomalies (67). The aberrant luminal recanalization theory proposed by Bremer (70) is an adequate explanation for duplications in those portions of the gastrointestinal tract that go through the "solid stage," such as the esophagus, small bowel, and colon. In the 5th or 6th week of intrauterine life, the foregut is covered by cells similar to those seen in the respiratory tract. This epithelium grows and obliterates the lumen and later produces secretions that form vacuoles in the intercellular space. The vacuoles line up longitudinally and eventually coalesce to form the new lumen. If for any reason some vacuoles fail to coalesce on the longitudinal axis, a cyst will form that may migrate laterally into the esophageal wall and become surrounded by the muscular layers. Owing to the elongation of the intrathoracic viscera and the dextrorotation of the stomach, these cysts are frequently found in the inferior portion of the esophagus and on its right side.

The duplicated segment has a thick wall of smooth muscle and is lined with alimentary tract mucosa. The lining mucosa may be the same as that in the segment it parallels, or it may be similar to that in some other portions of the alimentary tract, frequently gastric mucosa, in which case peptic ulceration of the duplication is a common finding (71). In the newborn and infant, symptoms are due to pressure on the adjacent lung or esophagus, leading to respiratory difficulties or dysphagia and vomiting. Complete duplication is a rare malformation, often associated with gastric duplication. Visualization of the duplicated segment in complete tubular form depends on its communication with the normal esophagus or stomach (Fig 22) and may not be appreciated until after surgical treatment for the gastric component (72).

View larger version (78K): [in this window] [in a new window] [Download PPT slide]   Figure 22.  Complete tubular esophageal duplication in an infant with history of cough and choking. Note the two channels (1 and 2). The duplicated one is located posterior to the normal esophagus.

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 23a.  Cystic esophageal duplication in a 2-year-old child with recurrent episodes of vomiting. (a) Esophagogram shows extrinsic compression on the left wall of the esophagus (arrows). (b) On a T1-weighted coronal MR image, a sharply defined low-signal-intensity mass (arrows) is seen adjacent to the left side of the esophagus. The mass showed high signal intensity on T2-weighted images.

View larger version (150K): [in this window] [in a new window] [Download PPT slide]   Figure 23b.  Cystic esophageal duplication in a 2-year-old child with recurrent episodes of vomiting. (a) Esophagogram shows extrinsic compression on the left wall of the esophagus (arrows). (b) On a T1-weighted coronal MR image, a sharply defined low-signal-intensity mass (arrows) is seen adjacent to the left side of the esophagus. The mass showed high signal intensity on T2-weighted images.

View larger version (176K): [in this window] [in a new window] [Download PPT slide]   Figure 24a.  Cystic esophageal duplication. (a) Chest radiograph shows a widening of the right superior mediastinum (arrows). (b) Contrast-enhanced CT scan demonstrates a fluid-filled thin-walled mass adjacent to the trachea and esophagus (arrows). (c) In a different patient, esophagogram shows an extrinsic compression of the right wall of the esophagus due to a mediastinal mass (arrows) corresponding to a duplication cyst.

View larger version (91K): [in this window] [in a new window] [Download PPT slide]   Figure 24b.  Cystic esophageal duplication. (a) Chest radiograph shows a widening of the right superior mediastinum (arrows). (b) Contrast-enhanced CT scan demonstrates a fluid-filled thin-walled mass adjacent to the trachea and esophagus (arrows). (c) In a different patient, esophagogram shows an extrinsic compression of the right wall of the esophagus due to a mediastinal mass (arrows) corresponding to a duplication cyst.

View larger version (132K): [in this window] [in a new window] [Download PPT slide]   Figure 24c.  Cystic esophageal duplication. (a) Chest radiograph shows a widening of the right superior mediastinum (arrows). (b) Contrast-enhanced CT scan demonstrates a fluid-filled thin-walled mass adjacent to the trachea and esophagus (arrows). (c) In a different patient, esophagogram shows an extrinsic compression of the right wall of the esophagus due to a mediastinal mass (arrows) corresponding to a duplication cyst.

	Vascular Anomalies

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 
Compression and displacement of the trachea and esophagus as a result of anomalous development of the aorta and its branches are not uncommon in the pediatric patient. A majority of patients are asymptomatic, but patients may present with respiratory and gastrointestinal symptoms (78). The anomalies that most frequently cause stridor are a double aortic arch, a right aortic arch with a left ligamentum arising from the descending aorta, and an aberrant right subclavian artery arising on the left and passing posterior to the trachea or retroesophageal right subclavian artery (79). The first two aortic arch anomalies are true complete vascular rings and are frequent causes of dysphagia lusoria. Rarely is a significant esophageal dysfunction associated with an aberrant retroesophageal right subclavian artery, which does not constitutes a true vascular ring and must be considered as representing persistence of the right-sided aortic elements (80).

Diagnosis and differentiation of various vascular anomalies are based primarily on the chest plain radiograph and the esophagogram (Figs 25–27).

View larger version (80K): [in this window] [in a new window] [Download PPT slide]   Figure 25a.  Aberrant right subclavian artery. (a) Anteroposterior esophagogram shows an oblique filling defect passing cephalad from left to right (pathognomonic indentation) (arrows). (b) Lateral view shows compression in the posterior wall of the esophagus (arrow).

View larger version (89K): [in this window] [in a new window] [Download PPT slide]   Figure 25b.  Aberrant right subclavian artery. (a) Anteroposterior esophagogram shows an oblique filling defect passing cephalad from left to right (pathognomonic indentation) (arrows). (b) Lateral view shows compression in the posterior wall of the esophagus (arrow).

View larger version (96K): [in this window] [in a new window] [Download PPT slide]   Figure 26a.  Aberrant left subclavian artery. (a) Anteroposterior esophagogram shows an oblique filling defect crossing the esophagus cephalad from right to left (arrowheads). (b) Lateral view shows a posterior esophagus indentation similar to that for the aberrant right subclavian artery (arrow). (c) Contrast-enhanced CT shows the aberrant left subclavian artery (arrows).

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 26b.  Aberrant left subclavian artery. (a) Anteroposterior esophagogram shows an oblique filling defect crossing the esophagus cephalad from right to left (arrowheads). (b) Lateral view shows a posterior esophagus indentation similar to that for the aberrant right subclavian artery (arrow). (c) Contrast-enhanced CT shows the aberrant left subclavian artery (arrows).

View larger version (117K): [in this window] [in a new window] [Download PPT slide]   Figure 26c.  Aberrant left subclavian artery. (a) Anteroposterior esophagogram shows an oblique filling defect crossing the esophagus cephalad from right to left (arrowheads). (b) Lateral view shows a posterior esophagus indentation similar to that for the aberrant right subclavian artery (arrow). (c) Contrast-enhanced CT shows the aberrant left subclavian artery (arrows).

View larger version (76K): [in this window] [in a new window] [Download PPT slide]   Figure 27a.  Double aortic arch. (a) Barium esophagogram shows bilateral extrinsic compressions on the esophagus (arrows), producing a reverse S-shaped appearance. (b) Three-dimensional MR angiogram shows a vascular ring that corresponds to a double aortic arch.

View larger version (124K): [in this window] [in a new window] [Download PPT slide]   Figure 27b.  Double aortic arch. (a) Barium esophagogram shows bilateral extrinsic compressions on the esophagus (arrows), producing a reverse S-shaped appearance. (b) Three-dimensional MR angiogram shows a vascular ring that corresponds to a double aortic arch.

The most common and serious complete type of vascular ring is the double aortic arch, which consists of anterior and posterior arches encircling the trachea and esophagus in a tight ring, joining distally to form a common descending aorta (82,83). The right portion and left portion of the double arch each gives rise to its own carotid and subclavian arteries. Patients with this anomaly usually have severe respiratory symptoms and some swallowing difficulty. The chest radiograph is rarely diagnostic in infants, but in older children bilateral indentation of the trachea may be visible. Posterior indentation of the trachea may be visible in the lateral view. Barium swallow is often diagnostic (Fig 27), showing a horizontal defect in the posterior wall of the esophagus at the level of the third or fourth thoracic vertebra.

This defect is caused by the posterior arch, usually the larger of the two, as it passes behind the esophagus. In the anteroposterior view, the esophagogram shows bilateral compressions of the esophagus. This results in a reverse S-shaped indentation of the esophagus due to the higher and larger right aortic arch relative to the lower and smaller left aortic arch (84).

A right aortic arch with a left ligamentum arising from the descending aorta is another type of vascular ring, considerably less common than the double aortic arch. The left ligamentum arteriosum passes from the left pulmonary artery to the descending aorta or to the left subclavian artery, coursing to the left of the trachea and esophagus. The ring formed by the aorta, pulmonary artery, and ligament may compress these structures. In this anomaly, the origin of the left subclavian artery frequently is dilated (Kommerell diverticulum) (85) (Fig 28).

View larger version (94K): [in this window] [in a new window] [Download PPT slide]   Figure 28a.  Right aortic arch. (a) Esophagogram shows a right-sided aortic arch (arrowheads) compressing the right lateral wall of the esophagus. (b) MR angiogram in the same patient shows an associated Kommerell diverticulum (arrow) at the base of the left subclavian artery.

View larger version (120K): [in this window] [in a new window] [Download PPT slide]   Figure 28b.  Right aortic arch. (a) Esophagogram shows a right-sided aortic arch (arrowheads) compressing the right lateral wall of the esophagus. (b) MR angiogram in the same patient shows an associated Kommerell diverticulum (arrow) at the base of the left subclavian artery.

The most common of the aortic arch anomalies, occurring in nearly 1% of the population, is an aberrant right subclavian artery originating from an otherwise normal left aortic arch (88,89). The anomalous vessel arises from the left side of the aortic arch and crosses the mediastinum obliquely from left to right behind the esophagus and trachea on its cephalad course, producing a characteristic and actually pathognomonic indentation on the esophagus (78,81,82). In esophagograms, this indentation is seen as an oblique filling defect extending from the left to right (Fig 26). This condition rarely causes symptoms, except for occasional mild dysphagia, so generally no other radiographic study is needed (89).

	References

Top Abstract Embryology Tracheobronchial Anomalies Anomalies of the Lung Esophageal Anomalies Vascular Anomalies References

 

1. Keslar P, Newman B, Oh KS. Radiographic manifestation of anomalies of the lung. Radiol Clin North Am 1991; 29:255-270.[Medline]
2. Skandalakis JE, Gray SW, Symbas P. The trachea and the lung. In: Skandalakis JE, Gray SW, eds. Embryology for surgeons. 3rd ed. Baltimore, Md: Williams & Wilkins, 1994; 414-450.
3. Ghaye B, Szapiro D, Fanchmps JM, Dondelinger RF. Congenital bronchial abnormalities revisited. RadioGraphics 2001; 21:105-119.[Abstract/Free Full Text]
4. Evans JA. Aberrant bronchi and cardiac vascular anomalies. Am J Med Genet 1990; 35:46-54.[CrossRef][Medline]
5. Burri PH. Fetal and postnatal development of the lung. Annu Rev Physiol 1984; 46:617-628.[CrossRef][Medline]
6. Laudy JAM, Wladimiroff JW. The fetal lung. I. Developmental aspects. Ultrasound Obstet Gynecol 2000; 16:284-290.
7. Langston C, Kida K, Reed M, Thurlbeck WM. Human lung growth in late gestation and in the neonate. Am Rev Respir Dis 1984; 129:607-613.[Medline]
8. Kauczor HU, Wolcke B, Fisher B, Mildenberger P, Lorenz J, Thelen M. Three-dimensional helical CT of the tracheobronchial tree: evaluation of imaging protocols and assessment of suspected stenoses with bronchoscopic correlation. AJR Am J Roentgenol 1996; 167:419-424.[Abstract/Free Full Text]
9. Benjamin B. Tracheomalacia in infants and children. Ann Otol Rhinol Laryngol 1984; 93:438-442.[Medline]
10. Griffiths H, Doull I, Williams RG, Marnane C. Tracheomalacia and breath holding: a case report. Arch Dis Child 2000; 83:340-341.[Abstract/Free Full Text]
11. Beasley SW, Qi BQ. Understanding tracheomalacia. J Pediatr Child Health 1998; 34:209-210.[CrossRef]
12. Reid L, Edward BD. The lung: its growth and remodeling in health and disease. AJR Am J Roentgenol 1977; 129:777-788.[Medline]
13. Sato E, Koyama S, Kamijyo H, Kobayashi O, Tereshima M, Kubo K. Respiratory distress due to tracheal compression by the dilated innominate artery. Eur Respir J 1999; 14:723-724.[Abstract]
14. Berdon WE. Ring, sling, and other things: vascular compression of the infant trachea updated from the mid century to the millenium—the legacy of Robert E. Gross, MD, and Edward B. D. Neuchauser, MD. Radiology 2000; 216:624-632.
15. Lee KH, Lee KH, Yoon CS, et al. Use of imaging for assessing anatomical relationships of tracheobronchial anomalies associated with left pulmonary artery sling. Pediatr Radiol 2001; 31:269-278.[CrossRef][Medline]
16. Hernandez RJ, Tucker GF. Congenital tracheal stenosis: role of CT and high kV films. Pediatr Radiol 1987; 17:192-196.[CrossRef][Medline]
17. Murphy PM, Lloyd-Thomas A, Elliott M. Management of congenital tracheal stenosis in infants. Br J Hosp Med 1990; 94:266-270.
18. O'Sullivan BP, Frassica JJ, Rayder SM. Tracheal bronchus: a cause of prolonged atelectasis in intubated children. Chest 1998; 113:537-540.[Abstract/Free Full Text]
19. Boyden EA. The distribution of bronchi in gross anomalies of the right upper lobe, particularly lobes subdivided by azygos vein and containing prearterial bronchi. Radiology 1952; 58:797-807.
20. Kuo CW, Lee YC, Perng RP. Tracheal bronchus associated with lung cancer: a case report. Chest 1999; 116:1125-1127.[Abstract/Free Full Text]
21. Ritsema GH. Ectopic right bronchus: indication for bronchography. AJR Am J Roentgenol 1983; 140:674-674.
22. Elmalci TT, Güler N, Aydogan U, Onursal E. Infantile lobar emphysema and tracheal bronchus in a patient with congenital heart disease. J Pediatr Surg 2001; 36:1596-1598.[CrossRef][Medline]
23. Siegel MJ. Mediastinum. In: Siegel MJ, eds. Pediatric body CT. Philadelphia, Pa: Lippincot Williams & Wilkins, 1999; 65-100.
24. Freeman SJ, Harvey PR, Goddar PR. Demonstration of supernumerary bronchus by computed tomographic scanning and magnetic resonance imaging. Thorax 1995; 50:426-427.[Abstract/Free Full Text]
25. Williams AJ, Schuster SR. Bronchial atresia associated with a bronchogenic cyst: evidence of early appearance of atretic segments. Chest 1985; 87:396-398.[Abstract/Free Full Text]
26. Oh KS, Dorst JP, White JJ. The syndrome of bronchial atresia or stenosis with mucocele and focal hyperinflation of the lung. Johns Hopkins Med J 1976; 138:48-53.[Medline]
27. Culiner TS, Grimens OF. Localised emphysema in association with bronchial cysts of mucocele. J Thorac Cardiovasc Surg 1961; 41:306-313.
28. Beigelman C, Howarth NR, Chartrand-Lefebvre C, Grenier P. Congenital anomalies of tracheobronchial branching patterns: spiral CT aspects in adults. Eur Radiol 1998; 8:79-85.[CrossRef][Medline]
29. McAdams HP, Kirejczyk WM, Rosado de Christenson ML, Matsumoto S. Bronchogenic cyst: imaging features with clinical and histopathologic correlation. Radiology 2000; 56:441-446.
30. Nobuhara KK, Gorski YC, La Quaglia MP, Shamberger RC. Bronchogenic cysts and esophageal duplications: common origins and treatment. J Pediatr Surg 1997; 32:1408-1413.[CrossRef][Medline]
31. Kim KW, Kim WS, Cheon JE, et al. Complex bronchopulmonary foregut malformation: extralobar pulmonary sequestration associated with a duplication cyst of mixed bronchogenic and esophageal type. Pediatr Radiol 2001; 3:265-268.
32. Nuchtern JG, Harberg FJ. Congenital lung cysts. Semin Pediatr Surg 1994; 3:233-243.[Medline]
33. Ashizawa K, Okimoto T, Shirafuji T, Kusano H, Ayabe H, Hayashi K. Anterior mediastinal bronchogenic cysts: demonstration of complicating malignancy by CT and MRI. Br J Radiol 2001; 74:959-961.[Abstract/Free Full Text]
34. Hantous-Zannad S, Charrada L, Mestiri I, et al. Radiological and clinical aspects of bronchogenic lung cysts: 4 case reports. Rev Pneumol Clin 2000; 56:249-254.[Medline]
35. Avni EF, Vanderelst A, Van Gansbeke D, et al. Antenatal diagnosis of pulmonary tumors: report of two cases. Pediatr Radiol 1986; 16:190-192.[CrossRef][Medline]
36. Winters WD, Effmann EL. Congenital masses of the lung: prenatal and postnatal imaging evaluation. J Thoracic Imaging 2001; 16:196-206.[CrossRef][Medline]
37. Albright EB, Crane JP, Shackelford GD. Prenatal diagnosis of a bronchogenic cyst. J Ultrasound Med 1988; 7:91-95.
38. Glazer HS, Siegel MJ, Sagel SS. Low-attenuation mediastinal masses on CT. AJR Am J Roentgenol 1983; 140:463-465.[Abstract/Free Full Text]
39. Lyon RD, McAdams HP. Mediastinal bronchogenic cyst: demonstration of a fluid-fluid levet at MR imaging. Radiology 1993; 186:427-428.[Abstract/Free Full Text]
40. Schneider P, Schwalbe E. Die morphologic der missbildungen des menschen und der thiere. Jena: Fischer 1912; 3:812-822.
41. Çay A, Sarihan H. Congenital malformation of the lung. J Cardiovasc Surg 2000; 41:507-510.[Medline]
42. Wu CT, Chen MR, Shih SL, Huang FY, Hou SH. Case report: agenesis of the right lung diagnosed by three-dimensional reconstrution of helical chest CT. Br J Radiol 1996; 69:1052-1054.[CrossRef][Medline]
43. Husain AN, Hessel RG. Neonatal pulmonary hypoplasia: an autopsy study of 25 cases. Pediatr Pathol 1993; 13:475-484.[Medline]
44. Cremin BJ, Bass EM. Retrosternal density: a sign of pulmonary hypoplasia. Pediatr Radiol 1975; 3:145-147.[CrossRef][Medline]
45. Hubbard AM, Adzick AS, Crombleholme TM, et al. Congenital chest lesions: diagnosis and characterizacion with prenatal MR imaging. Radiology 1999; 212:43-48.[Abstract/Free Full Text]
46. Kuwashima S, Nishimura G, Iimura F, et al. Low-intensity fetal lungs on MRI may suggest the diagnosis of pulmonary hypoplasia. Pediatr Radiol 2001; 31:669-672.[CrossRef][Medline]
47. Henk CB, Prokesch R, Grampp S, Strasser G, Mostbeck GH. Scimitar syndrome: MR assessment of hemodynamic significance. J Comput Assist Tomogr 1997; 21:628-630.[CrossRef][Medline]
48. Rutledge JM, Hiatt PW, Wesley Vick G, 3rd, Grifka RG. A sword for the left hand: an unusual case of left-sided scimitar syndrome. Pediatr Cardiol 2001; 22:350-352.[Medline]
49. Takeda S, Imachi T, Arimitsu K, Minami M, Hayakawa M. Two cases of scimitar variant. Chest 1994; 29:292-293.
50. Kivelitz DE, Scheer I, Taupitz M. Scimitar syndrome: diagnosis with MR angiogrphy. AJR Am J Roentgenol 1999; 172:1692-1700.
51. Kuga T, Inoue T, Sakano H, Zempo N, Oga A, Esato K. Congenital cystic adenomatoid malformation of the lung with an esophageal cyst: report of a case. J Pediatr Surg 2001; 36:E4.[CrossRef][Medline]
52. Stocker J, Madewell J, Drake R. Congenital cystic adenomatoid malformation of the lung: classification and morphologic spectrum. Hum Pathol 1977; 8:155-171.[Medline]
53. Ribet ME, Copin M-C, Sotos JG, Gosselin BH. Bronchioloalveolar carcinoma and congenital cystic adenomatoid malformation. Ann Thorac Surg 1995; 60:1126-1128.[Abstract/Free Full Text]
54. Lackner RP, Thompson AB, Rikkers LF, Galbraith TA. Cystic adenomatoid malformation involving a entire lung in a 22-year-old woman. Ann Throrac Surg 1996; 61:1827-1829.
55. Al-Salem AH, Adu-Gyamfi Y, Grant CS. Congenital lobar emphysema. Can J Anaesth 1990; 37:377-379.[Medline]
56. Stigers KB, Woodring JH, Kanga JF. The clinical and imaging spectrum of findings in patients with congenital lobar emphysema. Pediatr Pulmonol 1992; 14:160-170.[Medline]
57. Karnak I, Senocak ME, Ciftci AO, Büyükpamkçu N. Congenital lobar emphysema: diagnosis and therapeutic considerations. J Pediatr Surg 1999; 34:1347-1351.[CrossRef][Medline]
58. Thakral CL, Maji DC, Sajwani MJ. Congenital lobar emphysema: experience with 21 cases. Pediatr Urg Int 2001; 17:88-91.[CrossRef]
59. Myers NA. Congenital lobar emphisema. Aust NZ J Surg 1969; 30:32-35.
60. Frazier AA, Rosado de Christenson ML, Stocker JT, Templeton PA. Intralobar sequestration: radiologic-pathologic correlation. RadioGraphics 1997; 17:725-745.[Abstract]
61. Winters WD, Effmann EL. Congenital masses of the lung: prenatal and postnatalimaging evaluation. J Thorac Imaging 2001; 16:196-206.
62. Bratu I, Flageole H, Chen M-F, Lorenzo MD, Yazbeck S, Laberge J-M. The multiple facets of pulmonary sequestration. J Pediatr Surg 2001; 36:784-790.[CrossRef][Medline]
63. Cumming WA. Esophageal atresia and tracheoesophageal fistula. Radiol Clin North Am 1975; 13:277-286.[Medline]
64. Barnard CN. The genesis of intestinal atresia. Surg Forum 1956; 7:393-402.
65. Donoghue V. Neonatal gastrointestinal tract. In: Carty H, Brunelle F, eds. Imaging children. New York, NY: Churchill Livingstone, 1994; 250-260.
66. Botto LD, Khoury MJ, Mastroiacovo P, et al. The spectrum of congenital anomalies of the VATER asociation: an international study. Am J Med Genet 1997; 71:8-15.[CrossRef][Medline]
67. Benson JE, Olsen MM, Fletcher BD. A spectrum of bronchopulmonary anomalies associated with tracheoesophageal malformations. Pediatr Radiol 1985; 15:377-380.[CrossRef][Medline]
68. Berrocal T, Torres I, Gutiérrez J, Prieto C, del Hoyo ML, Lamas M. Congenital anomalies of the upper gastrointestinal tract. RadioGraphics 1999; 19:855-872.[Abstract/Free Full Text]
69. Kirkpatrick JA, Wagner ML, Pilling GPA. A complex of anomalies associated with tracheoesophageal fistula and esophageal atresia. AJR Am J Roentgenol 1965; 95:208-212.[Abstract/Free Full Text]
70. Plavsic BM, Robinson AE, Jeffrey RB, Jr. Gastrointestinal radiology New York, NY: McGraw-Hill, 1992; 612-628.
71. Tam PKH, Chan FL, Saing H. Diagnosis and evaluation of esophageal atresia by direct sagittal CT. Pediatr Radiol 1987; 17:68-70.[CrossRef][Medline]
72. Hertzberg BS, Bowie JD. Fetal gastrointestinal abnormalities. Radiol Clin North Am 1990; 28:101-114.[Medline]
73. Macpherson RI. Gastrointestinal tract duplications: clinical, pathologic, etiologic, and radiologic considerations. RadioGraphics 1993; 13:1063-1080.[Abstract/Free Full Text]
74. Bower RJ, Sieber WK, Kiesewetter WB. Alimentary tract duplications in children. Ann Surg 1978; 188:689-674.[Medline]
75. Arbona JL, Fazzi JGF, Mayoral J. Congenital esophageal cysts: case report and review of the literature. Am J Gastroenterol 1984; 79:177-182.[Medline]
76. Bremer JL. Diverticula and duplications of the intestinal tract. Arch Pathol 1944; 38:132-140.
77. Ildstad ST, Tollerud DJ, Weiss RG, Ryan DP, McGowan MA, Martin LW. Duplications of the alimentary tract: clinical characteristics, preferred treatment and associated malformations. Ann Surg 1988; 208:184-189.[Medline]
78. Herman TE, Oser AB, McAlister WH. Tubular communicating duplications of esophagus and stomach. Pediatr Radiol 1991; 21:494-496.[CrossRef][Medline]
79. Weiss LM, Fagelman D, Warhit JM. CT demonstration of an esophageal duplication cyst. J Comput Assist Tomogr 1983; 7:716-718.[Medline]
80. Rhee RS, Ray CG, Kravetz MH, et al. Cervical esophageal duplication cyst: MR imaging. J Comput Assist Tomogr 1988; 12:693-695.[Medline]
81. Bhutani MS, Hoffman BJ, Reed C. Endosonographic diagnosis of an esophageal duplication cyst. Endoscopy 1996; 28:396-397.[Medline]
82. Favara BE, Franciosi RA, Akers DR. Enteric duplications: thirty-seven cases. A vascular theory of pathogenesis. Am J Dis Child 1971; 122:501-506.
83. Holcomb GW, Gheissari A, O'Neill JA, Jr, Shorter NA, Bishop HC. Surgical management of alimentary tract duplications. Ann Surg 1989; 209:167-174.[Medline]
84. Gross RE, Neuhauser EBD. Compression of trachea or esophagus by vascular anomalies: surgical therapy in 40 cases. Pediatrics 1951; 7:69-73.[Abstract/Free Full Text]
85. Skandalakis JE, Gray SW, Ricketts R. The esophagus. In: Skandalakis JE, Gray SW, eds. Embryology for surgeons. 2nd ed. Baltimore, Md: Williams & Wilkins, 1992; 65-112.
86. Skandalakis JE, Gray SW, Symbas P. The thoracic and abdominal aorta. In: Skandalakis JE, Gray SW, eds. Embryology for surgeons. 2nd ed. Baltimore, Md: Williams & Wilkins, 1992; 976-1031.
87. Berdon WE, Baker DH. Vascular anomalies in the infant lung: rings, slings, and other things. Semin Roentgenol 1972; 7:39-47.[CrossRef][Medline]
88. Rubens M. The heart and great vessels. In: Carty H, Brunelle F, eds. Imaging children. London, England: Churchill Livingstone, 1994; 168-247.
89. Shuford WH, Sybers RG, Edwards FK. The three types of right aortic arch. Am J Radiol 1970; 109:67-74.[Abstract]
90. Swischuk LE. Plain film interpretation in congenital heart disease 2nd ed. Baltimore, Md: Williams & Wilkins, 1979; 98-114.
91. Jung JY, Almond CH, Saab SB, Lababidi Z. Surgical repair of right aortic arch with aberrant left subclavian artery and left ligamentum arteriosum. J Thorac Cardiovasc Surg 1978; 75:237-243.[Abstract]
92. Backer CL, Ilbawi MN, Idriss FS, DeLeon SY. Vascular anomalies causing tracheoesophageal compression: review of experience in children. J Thorac Cardiovasc Surg 1989; 97:725-731.[Abstract]
93. Gomes AS, Lois JF, George B, Alpan G, Williams RG. Congenital anomalies of the aortic arch: MR imaging. Radiology 1987; 165:691-695.[Abstract/Free Full Text]
94. Klinkhamer AC. Aberrant right subclavian artery: clinical and roentgenologic aspects. AJR Am J Roentgenol 1966; 97:438-446.[Abstract/Free Full Text]
95. Tonkin IL. Imaging of pediatric congenital heart disease. J Thorac Imaging 2000; 15:274-279.

This article has been cited by other articles:

				S. Furia, P. Biban, M. Benedetti, A. Terzi, M. Soffiati, and F. Calabro Postpneumonectomy-like syndrome in an infant with right lung agenesis and left main bronchus hypoplasia. Ann. Thorac. Surg., May 1, 2009; 87(5): e43 - e45. [Abstract] [Full Text] [PDF]

				J. R. Dillman, S. G. Yarram, and R. J. Hernandez Imaging of Pulmonary Venous Developmental Anomalies Am. J. Roentgenol., May 1, 2009; 192(5): 1272 - 1285. [Abstract] [Full Text] [PDF]

				Radiology Quiz Case 2: Diagnosis Arch Otolaryngol Head Neck Surg, May 1, 2009; 135(5): 518 - 519. [Full Text] [PDF]

				N. Teissier, M. Elmaleh-Berges, L. Ferkdadji, M. Francois, and T. Van Den Abbeele Cervical Bronchogenic Cysts: Usual and Unusual Clinical Presentations Arch Otolaryngol Head Neck Surg, November 1, 2008; 134(11): 1165 - 1169. [Abstract] [Full Text] [PDF]

				Z. Ming, S. Hong, and J. Biao Asplenia Syndrome With Bilateral Tracheal Bronchi Circulation, July 8, 2008; 118(2): 196 - 197. [Full Text] [PDF]

				E. Y. Lee, P. M. Boiselle, and R. H. Cleveland Multidetector CT Evaluation of Congenital Lung Anomalies Radiology, June 1, 2008; 247(3): 632 - 648. [Abstract] [Full Text] [PDF]

				S. Yedururi, R. P. Guillerman, T. Chung, R. M. Braverman, M. K. Dishop, C. M. Giannoni, and R. Krishnamurthy Multimodality Imaging of Tracheobronchial Disorders in Children RadioGraphics, May 1, 2008; 28(3): e29 - e29. [Abstract] [Full Text] [PDF]

				M. Loscertales, A. J. Mikels, J. K.-H. Hu, P. K. Donahoe, and D. J. Roberts Chick pulmonary Wnt5a directs airway and vascular tubulogenesis Development, April 1, 2008; 135(7): 1365 - 1376. [Abstract] [Full Text] [PDF]

				S.-J. Chen, W.-J. Lee, M.-T. Lin, J.-K. Wang, C.-I. Chang, I.-S. Chiu, and M.-H. Wu Left Pulmonary Artery Sling Complex: Computed Tomography and Hypothesis of Embryogenesis Ann. Thorac. Surg., November 1, 2007; 84(5): 1645 - 1650. [Abstract] [Full Text] [PDF]

				K. G. Ackerman, J. Wang, L. Luo, Y. Fujiwara, S. H. Orkin, and D. R. Beier Gata4 Is Necessary for Normal Pulmonary Lobar Development Am. J. Respir. Cell Mol. Biol., April 1, 2007; 36(4): 391 - 397. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only All Versions of this Article: e17v1 24/1/e17    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Berrocal, T. Articles by Gómez-León, N. Search for Related Content PubMed PubMed Citation Articles by Berrocal, T. Articles by Gómez-León, N.