Cancers that start in the gallbladder are usually adenocarcinomas, such as papillary adenocarcinoma (papillary cancer). Adenosquamous carcinomas, squamous cell carcinomas and carcinosarcomas may also start in the gallbladder.Cancers that form in the pancreas are one of two types: exocrine or neuroendocrine tumors (PNETs). Exocrine tumors usually are adenocarcinoma, acinar cell carcinoma, intraductal papillary-mucinous neoplasm (IPMN) and mucinous cystic neoplasm with an invasive adenocarcinoma. Neuroendocrine tumors of the pancreas usually include gastrinoma (gastrin), glucaganoma (glucagon), insulinoma (insulin), somatostatinoma (somatostatin), VIPoma (vasoactive intestinal peptide) and nonfuctional islet cell tumor (no hormones).