Functional Pancreatic Neuroendocrine Tumors

Functional pancreatic neuroendocrine tumors (pNETs) are rare tumors characterized by both inappropriately elevated hormonal production and subsequent clinical symptoms secondary to that overproduction. They are a heterogeneous group of tumors in terms of their presentation, clinical syndromes, malignant potential, and management. Goals of treatment must focus on both their oncologic outcomes as well as the associated endocrinopathies. This chapter will focus on sporadic functional pNETs; their epidemiology, pathology, diagnostic approach, and management. Individual types of functional pNETs will be discussed in detail, including insulinomas, gastrinomas, and the rarer subtypes. Numerous local, loco-regional, and systemic treatment options are available, and this chapter will discuss the available data for each and how to best utilize each one for a given patient. The natural history of most pNETs is an indolent one, and most patients will require a number of different treatments for optimal long-term management of their disease.