Brunner's glands are found in a part of the digestive system known as the duodenum. The duodenum is the section of gut through which food passes after leaving the stomach. These glands produce alkaline mucus, which neutralizes acid from the stomach as it enters the duodenum. As long as Brunner's glands function normally, this mucus helps protect the duodenal lining. Occasionally, the glands can grow abnormally and develop into a tumor, but this is typically benign, or non-cancerous.
The duodenal glands which came to be known as Brunner's glands were named after the Swiss anatomist Johann Conrad Brunner. He first described the glands in 1687. At the junction between the stomach and the intestine, the pyloric glands of the stomach end and are replaced by the duodenal Brunner's glands. These glands extend through the duodenum, although they are not found beyond the sphincter of Oddi. The sphincter of Oddi is a valve, located in the wall of the duodenum, which controls the flow of digestive juices from the liver and pancreas into the gut.
Brunner's glands are located in a part of the duodenal wall known as the submucosa. This is a layer of tissue full of blood vessels and nerves which supports the mucosa, or inner lining, of the gut. The glands are densely packed inside the submucosa, filling it completely. An individual gland may secrete its mucus directly into the intestine, or its secreting tubes or ducts could join up with other glands in the gut wall.
Rarely, a disorder known as hyperplasia can affect Brunner's glands. The cells which make up the glands increase until abnormal numbers are present, forming a tumor. Most often there are no symptoms, but sometimes abdominal pain occurs at night, or after meals, and there may also be bleeding from the gut. This is usually in such small amounts that it is not visible, but it can cause anemia and occasionally patients may pass or vomit blood. Although complications are uncommon, a Brunner's gland tumor can sometimes block the gut.
Brunner's gland hyperplasia is diagnosed using techniques such as endoscopy and CT scans, in order to view the tumor. A sample of the growth may be taken using an endoscope, a flexible viewing instrument with associated surgical tools. Although a tumor in this area is not usually cancerous, tumors are typically removed surgically if there are symptoms, or if the diagnosis is uncertain.
