Pancreatic Neuroendocrine Tumors in the 21 st Century—An Update

Abstract

Pancreatic neuroendocrine tumors (PNETs) are rare, reported to account for less than 1%-2% of all pancreatic tumors. This, however, is likely an underestimation , as improved radiologic techniques and heightened awareness have resulted in an increase in the detection of incidentalomas, with estimations of true prevalence as high as 10%. The term "PNET" is an umbrella name that encompasses a heterogeneous group of neoplasms each with distinct clinical presentations, diagnostic radiographic features, management principles, and tumor/patient outcomes. In this context, accurate diagnosis is challenging, and management guidelines remain unclear. A high degree of clinical suspicion is required for best patient management. This manuscript provides an update on PNETs in the 21 st century, in which we reexamine the terminology , epidemiology, classification, etiopathogenesis, radiographic and histopa-thologic diagnostic features, management for localized and metastatic disease, as well as a review of features defining functional and non-functional PNETS, and finally deliberates on the prognosis and predictive features of this unpredictable and largely unfathomable neoplasm.