Foregut duplication cyst of the stomach.

Foregut duplication cyst of the stomach is an extremely rare disease entity. A 35-year-old Korean man presented with epigastric pain. An abdominal cystic mass, measuring 7 x 6 x 5 cm, was found in the lesser curvature of the stomach. The cyst was unilocular with a grey-white, rubbery wall. Microscopically, the cyst wall was lined by pseudostratified ciliated, columnar epithelium and gastric mucosa with a complete lining of smooth muscle bundles. Although the origin of this lesion remains uncertain, this case suggests that the gastric cyst arose from the embryonic foregut and showed differentiation toward respiratory and gastric structures.