What are somatostatinomas?

Somatostatinomas are a type of neuroendocrine tumour (NET). They start in neuroendocrine cells that make the hormone somatostatin. There are neuroendocrine cells in most organs of our body, including the small bowel (duodenum) and pancreas.

Most somatostatinomas make large amounts of the hormone somatostatin. This hormone controls the production of other hormones by the pancreas. It also controls how the gut works. Somatostatinomas are a type of functioning pancreatic NET.

The pancreas and duodenum

The pancreas and duodenum are part of our digestive system.

The pancreas is a large gland that makes digestive juices and hormones. The juices flow down a tube (pancreatic duct) into the duodenum. The duodenum is the first part of the small bowel. 

Another duct called the bile duct joins the duodenum to the liver and the pancreas. The bile duct comes down from the gallbladder and liver and joins the duodenum right next to the pancreatic duct.

Where it starts

More than 50 out of every 100 somatostatinomas (50%) start in the pancreas. Pancreatic tumours usually start in the widest part of the pancreas (head). 

More than 40 out of every 100 somatostatinomas (40%) start in the small bowel (duodenum). 

More rarely somatostatinomas can start in:

• the middle part of the small bowel (jejunum)
• a tube called the cystic duct that connects the gallbladder to the common bile duct

How common it is

Somatostatinomas are very rare. Only 1 out of every 100 pancreatic NETs (1%) diagnosed every year are somatostatinomas. Between 4 to 12 people in every million develop a NET of the pancreas every year.

Cancer or non cancer?

Somatostatinomas are cancers. Somatostatinomas usually grow slowly and the symptoms can be vague. So people are often diagnosed when the cancer has already spread to other parts of the body (secondary tumours or metastases). 

The most common places where somatostatinomas spread to is the liver and lymph nodes.