Some different types of pancreatic tumors include exocrine tumors and neuroendocrine tumors, according to the Pancreatic Cancer Action Network. These are types of cancer that form on the two different types of cells that compose the pancreas: endocrine and exocrine.
Over 95 percent of pancreatic tumors are exocrine tumors, which means they form on exocrine cells of the pancreas that are responsible for producing digestive enzymes, explains the Pancreatic Cancer Action Network. The vast majority of pancreatic exocrine tumors are adenocarcinomas.
Less than 5 percent of pancreatic tumors are neuroendocrine and develop from the abnormal growth of endocrine cells, which are responsible for the release of hormones. Endocrine tumors are also referred to as islet cell tumors, according to Pancreatic Cancer Action Network.