Giant Brunner's gland hamartoma causing retrograde jejuno-duodenal intussusception: A case report.

Brunner's gland hamartoma is a rare benign duodenal tumor. It occurs in Brunner's glands, which are found in the duodenum and produce secretions that protect the duodenum from pancreatic enzymes, gastric acid, and other agents. Endoscopic or surgical resection is required for these hamartomas.