Congenital and Neonatal Abnormalities

Chapter 100

Congenital and Neonatal Abnormalities

Although they are relatively rare, congenital and neonatal abnormalities of the stomach may present in a clinical spectrum ranging from asymptomatic to complete gastric obstruction. These abnormalities include such entities as duplication cysts, diverticula, microgastria, and anomalies involving the antropyloric region.

Gastric Duplication Cyst

Overview: Duplication cysts may occur anywhere along the gastrointestinal tract, from the mouth to the rectum. They typically occur on the mesenteric surface of the viscus to which they are attached. More than 80% are spherical and do not communicate with the lumen, whereas approximately 18% are tubular and may communicate with the lumen of the adjacent bowel. Duplication cysts are named by the segment of gut to which they are attached, not by the type of mucosa lining the lumen, which may include representatives of all portions of the gastrointestinal tract, including the pancreas.1 Gastric duplication cysts are rare and comprise approximately 4% to 7% of intestinal duplications.1,2

Although the cysts usually are located along the greater curvature of the stomach, they may occur in other regions of the stomach, including the pylorus,3–5 in addition to ectopic sites.6 Most gastric duplication cysts are spherical and typically do not communicate with the gastric lumen. Histologically, the cysts usually are lined with gastric mucosa.2 Ectopic pancreatic tissue has been reported in approximately 37% of cases,1,7,8 with rare reported communication with the pancreatic ductal system.7

Clinical Presentation: Gastric duplication cysts occur more frequently in females at a ratio of 2 : 1.14 If it is not discovered prenatally on ultrasound,15,16 postnatal clinical presentation usually occurs during the first year of life17 with symptoms including intestinal obstruction, a palpable mass, gastrointestinal bleeding, abdominal pain, and hematemesis18,19 or melena.20 Uncommon complications of gastric duplication cysts include pancreatitis as a result of ectopic pancreatic tissue with perforation and pseudocyst formation21 and gastric outlet obstruction simulating hypertrophic pyloric stenosis.4,22,23

Imaging: Although gastric duplication cysts may be evident on plain radiography as a masslike density in the upper abdomen,18 the low sensitivity and specificity limits the utility of plain radiography. Gastrointestinal contrast examination may demonstrate an effect of the mass on the adjacent hollow viscus by the cyst (Fig. 100-1), and uncommonly it may demonstrate communication between the stomach and the cyst. Ultrasonography using a high-frequency transducer is an excellent imaging modality for characterization of these cystic masses, which often demonstrate the “gut signature” or “double-wall” sign, representing the inner hyperechoic mucosal layer and peripheral hypoechoic muscle layers typical of the gastrointestinal tract (Figs. 100-1, B, and 100-2); free fluid may be found in cases of perforation (Fig. 100-3). Cysts may be completely anechoic or may contain septations and internal echoes representing proteinaceous material, blood products, or debris related to infection24 (see Fig. 100-2). Computed tomography (CT) demonstrates a well-circumscribed homogeneously low-attenuating mass in the left upper quadrant. Peripheral enhancement, wall thickening, and heterogeneous attenuation of the cyst wall may be present if complicated by inflammation. On magnetic resonance imaging (MRI), the cysts exhibit fluid characteristics at T1 and T2 weighting, but the signal may increase on T1-weighted sequences in the presence of hemorrhage or other proteinaceous material. Imaging with technetium 99m–pertechnetate is very helpful when gastric mucosa lines the cysts.25 Meticulous technique is necessary to differentiate the duplication cyst from the adjacent stomach; multiple views may be required. Single photon emission tomography CT may be useful in defining the abnormality.

Gastric Diverticula

Clinical Presentation: Although most gastric diverticula are clinically asymptomatic, symptomatic lesions in children tend to present in early childhood and adolescence. The symptoms can range from nonspecific complaints such as recurrent abdominal pain, nausea, and vomiting to massive hemorrhage and perforation; such symptoms may relate to the presence of ectopic pancreatic tissue within the diverticula, causing erosions and ulceration.29,3133 Large antral partial diverticula can cause partial gastric outlet obstruction by compression or intussusception of the antropyloric region (Fig. 100-4).

Congenital Microgastria

Overview: Congenital microgastria is a rare anomaly of the pediatric gastrointestinal tract characterized by a small, tubular stomach, typically associated with a distended esophagus. In persons with microgastria the stomach is lined by normal gastric mucosa but the total cell mass is significantly reduced.35,36 Agastria, or complete absence of the stomach, is the most extreme form of microgastria.

Congenital microgastria is almost always accompanied by other congenital anomalies; isolated congenital microgastria is extremely rare. Associated congenital anomalies include a wide range of entities such as heterotaxy with asplenia and malrotation,37 congenital diaphragmatic hernia,38 tracheoesophageal clefts, hiatal hernia,36 jaw and palate abnormalities,39 DiGeorge syndrome, primary ciliary dyskinesia,40 central nervous system abnormalities, and vertebral, cardiac, renal, and limb reduction anomalies (VACTERL association). It has been suggested that microgastria in association with limb reduction defects and central nervous system anomalies may have an autosomal recessive mode of inheritance.41,42

Dec 20, 2015 | Posted by in PEDIATRIC IMAGING | Comments Off on Congenital and Neonatal Abnormalities
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