Universidad de Carabobo. Valencia. Venezuela

Introduction
The first duplication of the gastrointestinal tract was first described by Calder (4) in 1733, but the term intestinal duplication was first used by Fitz (5) in 1884. The term was not widely used until popularized by Ladd (13) in the 1930s, with further classifications by Gross (8) in the 1950s.
Gastrointestinal duplications constitute a rare group of malformations, which vary in site, size, appearance and fetal signs. Ladd (13) introduced the term "duplication of the intestinal tract" to encompass a group of congenital anomalies that have three characteristics:

1. Firstly, they have a well developed coat of smooth muscle;
2. Secondly, their epithelial lining represents some part of the alimentary tract and
3. Thirdly, they are attached to some part of the alimentary tract.

Duplications are either cystic or tubular in shape.  Singh et al (14) present a case of gastric duplication that was successfully managed surgically, and the patient is doing well at 2 years of follow up.
Congenital pyloric atresia was first described by Calder (4) in 1749, is a very rare malformation with an estimated incidence of 1 per million newborns (18).

Synonyms, key words, and related terms
Duplication cyst, enteric cyst, enterocystomas, enterogenous cysts, supernumerary accessory organs, stomach duplex, congenital pyloric atresia.

Incidence
Gastric duplication is extremely rare (8). Although the exact incidence is unknown, Potter (20) reported 2 cases in more than 9000 fetal and neonatal autopsies.  Gastric duplications cysts account for less than 5% of all enteric duplications (11, 16, 23). As duplication it is attached to its origin, has a well developed smooth muscle coat and gastric epithelial lining (2). Congenital pyloric atresia  is a very rare anomaly that constituted less than 1% of all upper gastrointestinal atresias (1). Although congenital pyloric atresia  can occur in isolation, but not uncommonly it is seen in association with either other gastrointestinal artesian or duplications. Probably this is the first report about association of gastric duplication cyst in association with pyloric atresia in the original stomach.

Etiology
Because duplication of the alimentary tract takes many different forms, the application of a single embryologic theory is not likely to be considered valid. This has led to the proposal of several different theories (1, 2, 3, 7, 10, 18, 23, 24) in an attempt to explain the embryologic events that culminate in intestinal duplication. Various theories have been postulated regarding the origin of duplication cysts, like;

• abortive attempts of twinning;
• phylogenetic reversion;
• adhesions between endoderm and neuroectoderm;
• persistence of embryonic diverticula;
• errors in epithelial recanalization (believed to occur between the fifth and eighth week of gestation);
• fusion of longitudinal folds, and
• vascular compromise during early organogenesis.

The exact pathogenesis of congenital pyloric atresia is not now. Three hypotheses (18) were proposed to explain this association:

• errors in epithelial recanalization;
• vascular compromise during early organogenesis, and
• scarring and fibrosis as a result of intrauterine sloughing of the mucous membranes.

The congenital pyloric atresia can occur as an isolated lesion or in association with other genetically determined conditions such as epidermolysis bullosa, aplasia cutis congenital or form part of the hereditary multiple intestinal atresias syndrome. In other hands the congenital pyloric atresia, epidermolysis bullosa and aplasia cutis congenital are three genetically determined conditions and their occurrence together is more likely the result of closely linked abnormal genes (Ahmed).
The congenital pyloric atresia can be classified intro three types (18):

• Pyloric membrane or diaphragm,
• Pyloric atresia without a gap, and
• Pyloric atresia with a gap.

Case report
A 32-year-old woman, at 37 weeks of pregnancy, was referred for ultrasound targeted scan for presenting polyhydramnios and two abdominal cysts. The study showed bilateral cysts in abdominal cavity. The abdominal perimeter was at the 95th percentile. The coronal and axial abdominal reveled the following images:

Delivery occured by cesarean section at 39 weeks delivering a male newborn weighing 3400 gr., with abdominal distention and clinical sign of intestinal obstruction. The definitive diagnosis was Gastric duplication cyst in association with pyloric atresia The patient was treated by excision of duplication cyst, and pyloro-duodenostomy and his outcome was good.

                                                          
Discussion
Gastric duplication is one of the rare causes of gastric outlet obstruction in the neonates and the other causes of gastric outlet obstruction being congenital hypertrophic pyloric stenosis, congenital antral web and pyloric atresia which should be included in the differential diagnosis.
Duplications are tubular or cyst structures composed of intestinal mucosa and muscle that are usually closely adherent to some part of the gastrointestinal tract  and the mucosa is often  similar to that of the portion of bowel to which attached, the lumen is generally cystic  and is filled with clear mucus secreted by the cells of the mucosal lining (4).
Microscopically the cyst is lined by gastric mucosa or a less well differentiated columnar mucosa (2). Stockman (22) reported a duplication of the rectum containing gastric mucosa.
A recent review of literature, cited by Michalsky  and Besner (18), regarding alimentary tract duplications in more than 500 patients reveals a widely varied anatomic distribution approximately 75% of duplications have been reported to be located within the abdominal cavity, while the remaining is pure intrathoracic (20%) or thoracoabdominal (5%). Jejune and ilea lesions are the most commonly encountered (53%), followed by mediastinal (18%), colonic (13%), gastric (7%), duodenal (6%), rectal (4%), thoracoabdominal (2%), and cervical (1%). Seventy-five percent of duplications are considered cystic, with no communication to adjacent intestine, while the remaining duplications are true cylindrical structures that may or may not have one or more direct communications across the common septum.
Gastric duplications are typically no communicating cystic structures located along the greater curve or posterior aspect of the stomach but have been reported at the level of the pylorus and may be mistaken for hypertrophic pyloric stenosis.
GD usually presents with an upper abdominal cyst, vary in length from a few to several centimeters. 
Pyloric atresia is an extremely rare condition representing less than 1% of all atresias of the alimentary tract (18). Rarer still is the association of pyloric atresia with other intestinal atresias. Al-Salem et al. in 1997 could find only eight such cases reported in the literature prior to their case (1). Further, only 5 cases incuding theirs, had combination of pyloric atresia with duodenal atresia.

There are three distinct groups of pyloric atresias:

1. isolated pyloric atresia; 
2. pyloric atresia in association with other alimentary tract atresias; and 
3. pyloric atresia in association with genetic disorders such as epidermolysis bullosa and aplasia cutis congenita.

The diagnosis should be suspected when an infant usually a female comes with features of gastric outlet obstruction. Ultrasound and CT scan of abdomen are highly contributive in the diagnosis of gastric duplication cyst.  Duplications can be found along the entire alimentary tract (Figure 1), the most common site being the ileum and colon. 

Management
We found in literature (1, 7, 8, 11, 12, 15, 16, 18, 19, 21, 23, 24) that gastric duplication are managed surgically by simple excision, by dissecting the common wall between the stomach and the duplication cyst, and usually it can be done easily without entering the stomach. But in cases where one does not get a plane of dissection in the common wall one should excise the common wall and suture the gastric defect as leaving behind the common wall (gastric epithelium) would expose the child to inflammatory complications. In this case the patient was treated by excision of duplication cyst, and pyloro-duodenostomy.

References
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