A low or intermediate grade well differentiated tumor with neuroendocrine differentiation that arises from the pancreas. It is characterized by the presence of a clinical syndrome that results from hormone hypersecretion. The disease is Monarch Disease Ontology entry MONDO_0023206 (functional pancreatic neuroendocrine tumor). Also known as: functional pancreatic NET, functioning PNET, functioning pancreatic NET, functioning pancreatic endocrine tumor, functioning pancreatic endocrine tumour, functioning pancreatic neuroendocrine tumor, functioning pancreatic neuroendocrine tumour, functioning well differentiated pancreatic endocrine neoplasm.