Duplication cysts constitute a rare group of malformations that can occur anywhere along the gastrointestinal tract. Gastric duplications cysts account for 4% of all enteric duplications, approximately 17 cases per million births. With the present report, we intend to show the findings of an infrequent pathology, as well as to show the usefulness of the magnetic resonance in their prenatal diagnosis.
Gastrointestinal duplications are tubular or cyst structures composed of intestinal mucosa and muscle that are usually closely adherent to some part of the gastrointestinal tract. Their mucosa is often similar to that of the portion of bowel to which is attached, and the lumen is generally cystic with clear mucus secreted by the cells of the mucosal lining. Approximately 75% of duplications are located within the abdominal cavity, while the remaining are intrathoracic (20%) or thoracoabdominal (5%). Seventy five percent of duplications are considered cystic, without communication to adjacent intestine, while the remaining are 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 curvature or antrum, although more rarely have been reported at the level of the pylorus. Usually they present as a cyst in the upper abdomen, which may vary in length from a few to several centimeters. Ultrasound may reveal the inner echogenic mucosal and outer hypoechoic muscle layers that are typical of a gastrointestinal tract duplication although it is difficult to visualize in prenatal examinations.
With infrequent or inconclusive ultrasound findings, the realization of an MRI can confirm the presumptive ultrasound diagnosis, providing additional information on the malformation site and the nature and relationship with other organs, thus contributing to treatment planning.