Anatomic disorders of the esophagus in children can be congenital or acquired. The most common congenital disorder of the esophagus is esophageal atresia (EA), which can be present with or without a tracheoesophageal fistula (TEF). Other congenital esophageal disorders include esophageal webs, duplications, laryngotracheoesophageal clefts (LTEC), and esophageal stenosis from extrinsic (vascular rings) or intrinsic sources. Acquired disorders of the esophagus include strictures due to foreign body or caustic injury, gastroesophageal reflux, eosinophilic esophagitis, or diverticula.
PATHOGENESIS AND EPIDEMIOLOGY
The pathogenesis of congenital esophageal malformations remains unknown and likely involves multiple genes and gene-environment interactions. Around day 26 or 27 of gestation, a ventral diverticulum is formed from the caudal end of the primitive pharyngeal foregut. This laryngotracheal diverticulum undergoes elongation and differentiation and eventually forms the larynx, trachea, bronchi, and lungs. In order to separate the dorsal foregut (future esophagus) from the ventral laryngotracheal diverticulum, longitudinal tracheoesophageal folds fuse to form a septum that completely separates these structures (Fig. 387-1). The traditional embryologic theory has held that failure of these folds to completely form, or improper timing of their formation, leads to the anomalies of EA and/or TEF. However, investigators have found little evidence to support that lateral folds forming a tracheoesophageal septum occurs at all. Genetics from associated conditions, however, has provided some insight. For example, the association of VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) and hydrocephalus is related to mutations in the FANCC, FANCD1 and FANCD2, FACCG, FANCB, and PTEN genes. Chromosomal abnormalities associated with EA-TEF include DiGeorge syndrome; Opitz syndrome; CHARGE (coloboma, heart defect, atresia choanae [also known as choanal atresia] retarded growth and development, genital abnormality, and ear abnormality) syndrome; and trisomy 13, 18, and 21, among others.
Schematic diagram demonstrating the development of the laryngotracheal diverticulum from the primitive pharyngeal foregut. Cross-sectional views show the tracheoesophageal folds creating a septum dividing the trachea and esophagus.
The embryogenesis of the various types of congenital esophageal stenosis is thought to be similar. An esophageal web is considered by some to represent a variant of EA. The web membrane is composed of squamous epithelium on both sides and often has a small opening, which is why it often does not present in the first day or 2 of life. Also, similar to EA-TEF, the embryology of esophageal stenosis secondary to tracheobronchial remnants is hypothesized to be due to disordered separation of the primitive foregut. Lastly, the pathogenesis of esophageal stenosis due to fibromuscular hypertrophy is also unknown but may be similar to that of congenital pyloric stenosis.
The embryology of LTEC is likewise not well understood. One recent theory suggests initial normal development of the trachea and esophagus followed by fusion of the 2 structures ...