Pancreatic neuroendocrine tumors (also known as islet cell tumors or islet cell carcinoma) are a type of neuroendocrine tumor found in the pancreas.

Only 5 percent of pancreatic tumors arise in the islet cells. The vast majority of tumors found in the pancreas are adenocarcinoma, which is more commonly referred to as pancreatic cancer.

Some pancreatic neuroendocrine tumors are functional, which means they produce excess hormones that can lead to a variety of hormone-related symptoms. Depending on the hormones produced by the tumor, pancreatic neuroendocrine tumors can cause a variety of symptoms, including:
diabetes
hypoglycemia (low blood sugar)
gallstones
stomach ulcers
severe diarrhea
sudden growth of the hands and feet (acromegaly)