Congenital anomalies of the tubular gastrointestinal tract

Abstract

Congenital anomalies of the tubular gastrointestinal tract are an important cause of morbidity not only in infants, but also in children and adults.

The gastrointestinal (GI) tract, composed of all three primitive germ layers, develops early during embryogenesis. Two major steps in its development are the formation of the gut tube (giving rise to the foregut, the midgut and the hindgut), and the formation of individual organs with specialized cell types.

Formation of an intact and functioning GI tract is under strict control from various molecular pathways. Disruption of any of these crucial mechanisms involved in the cell-fate decision along the dorsoventral, anteroposterior, left-right and radial axes, can lead to numerous congenital anomalies, most of which occur and present in infancy. However, they may run undetected during childhood.

Therapy is surgical, which in some cases must be performed urgently, and prognosis depends on early diagnosis and suitable treatment.

A precise pathologic macroscopic or microscopic diagnosis is important, not only for the immediate treatment and management of affected individuals, but also for future counselling of the affected individual and their family. This is even more true in cases of multiple anomalies or syndromic patterns.

We discuss some of the more frequent or clinically important congenital anomalies of the tubular GI, including atresia's, duplications, intestinal malrotation, Meckel's diverticulum and Hirschsprung's Disease.

Keywords: Hirschsprung Disease; gastrointestinal malformations; gastrointestinal tract; intestinal atresia; intestinal duplication.

Figure 1.

Types of esophageal atresia (EA) and tracheoesophageal fistula (TEF) according to the Gross classification: (A) EA without TEF (8%); (B) EA with proximal TEF (2%); (C) EA with distal TEF (85%); (D) EA with distal and proximal TEF (1%), and (E) TEF in the absence of EA (H-type TEF; 4%).

Figure 2.

Types of intestinal atresia according to the Grosfeld classification: Type I atresia is characterized by an intact bowel wall and a transluminal septum which causes proximal dilatation and collapse of the distal intestinal segment. In type II atresia the two blind-ending pouches are connected by a fibrous band, located along the edge of the intact mesentery. Type IIIa is similar to type II but is accompanied by a small mesenteric defect. Type IIIb is characterized by proximal jejunal atresia, an extensive mesenteric defect with loss of the normal blood supply and subsequent coiling of the ileum around the ileocolic artery. Type IV is defined as the presence of multiple atresias (types I, II, and III)(“string of sausages”).

Figure 3.

Plain abdominal X-ray displaying the classic double-bubble sign in a patient with duodenal atresia.

Figure 4.

Type I and II atresia’s according the Grosfeld classification: (a) Intraoperative image of ileal type I atresia according to the Grosfeld classification displaying dilatation of the proximal intestinal tract and a collapsed distal intestinal segment; (b) Histology of a fibrous band in type II atresia reveals a partially intact muscularis propria with fibrous obliteration of the lumen (H&E, x 50); (c) Higher magnification of serial sections revealed calcification and granulation tissue, suggestive of intrauterine ischemia and healing (H&E, x 200).

Figure 5.

Intraoperative image of the “apple peel deformity” or atresia type IIIb according to the Grosfeld classification.

Figure 6.

Location and incidence of duplications along the tubular gastrointestinal tract.

Figure 7.

Meckel diverticulum: (a) Intraoperative image of ileal Meckel diverticulum; (b) Histology of Meckel diverticulum with extopic endocrine and exocrine pancreatic tissue within the muscular wall.

Figure 8.

(a) Ganglion cells of the myenteric plexus from a normally innervated colon biopsy (H&E, x 400); (b) Calretinin immunohistochemistry displaying ganglion cells with nuclear and cytoplasmic positivity from a normally innervated tissue sample (x 400); (c) Hypertrophic submucosal nerves in a patient with HSCR (H&E, x 200).