Carcinoid in a gastrointestinal duplication.

This is a report of a 12-year-old boy having gastric duplication with foci of carcinoid. He complained of right abdominal pain. Physical examination showed a cystic mass in the right abdomen. It was excised operatively. The mass was a duplication cyst composed of gastric mucosa with a muscle layer. Foci of carcinoid was detected in the muscle layer. The tumor cells involved nerve fibers but did not extend to the subserosa. Postoperative blood serotonin and histamine levels were normal. The patient is healthy without signs of recurrence 17 months after operation. This is the second case of gastrointestinal duplication with foci of carcinoid. The findings indicate that careful histologic examination is necessary to determine the exact nature of the cyst.