Less common types of pancreatic neuroendocrine tumors

Abstract

Somatostatinomas are rare neuroendocrine tumours (NETs) that arise in the pancreas or duodenum. They are the fifth most common pancreatoduodenal NET (after insulinomas, non-functioning tumours, gastrinomas and VIPomas), with an incidence of 1 in 40 million [1-3]. They tend to be non-functioning, although they are rarely active and can produce a spectrum of symptoms called 'somatostatinoma syndrome' [4-6]. A degree of discord exists regarding the functional component of a somatostatinoma; some clinicians argue that a 'syndrome' of clinical symptoms must be present for the diagnosis of somatostatinoma and others that the diagnosis is purely immunohistochemical [7]. As most of these tumours are biochemically inert, they are either detected incidentally or by causing mass-effect pressure symptoms, and most will have metastasised by the time of diagnosis [6, 8, 9].