Intestinal cancer. Light micrograph of a section through an adenocarcinoma (cancer) of the sphincter of ampulla (sphincter of Oddi) - a muscular valve that controls the flow of digestive juices (bile and pancreatic juice) from the pancreatic duct and common bile duct, into the second part of the duodenum (the first section of the small intestine). Adenocarcinomas are the most common form of intestinal cancer.