Synchronous Insulinoma and Glucagonoma: A Review of the Literature

Pancreatic neuroendocrine tumors (PNETs) are pancreatic neoplasms with neuroendocrine features, divided into functioning and non-functioning. The non-functioning PNETs are the largest group, and their morbidity is the result of their potential to invade surrounding tissues and metastasize. The functioning PNETs produce hormonal symptoms due to over-secretion of specific hormones. They constitute 1% to 2% of all pancreatic tumors. The use of novel imaging methods has rendered their detection more frequent. Insulinoma, the most common functioning PNET, comprises 35-40% of all functioning PNETs. Its clinical presentation is due to hyperinsulinemia and the subsequent hypoglycemia. Glucagonoma accounts for 5% of all PNETs and is the fourth most frequent functioning PNET, following insulinoma, gastrinoma, and vipoma. Its symptoms are due to the massive secretion of glucagon and ensuing hyperglycemia. The co-existence of two PNETs is a very rare entity. This report aimed to describe cases of concomitant insulinomas and glucagonomas.

A review of the literature was performed using the PubMed database and Cochrane library aiming to identify reported cases of concomitant pancreatic insulinoma and glucagonoma. Specifically, the research was conducted using the keywords, separately and in various combination, including insulinoma, glucagonoma, cystic, pancreatic neuroendocrine tumors and hypoglycemia. Only publications in English were included in the present study.

A total of 8 cases of concomitant pancreatic insulinoma and glucagonoma were identified, corresponding to the period 1992-2021.

Concomitant insulinoma and glucagonoma are rare and challenging. A multidisciplinary approach is necessary for diagnosis, prognosis, and therapy.