Insulinoma

Abstract

Insulinoma is a rare neuroendocrine tumor with an incidence of 4 per 1 million persons per year, which may occur as a unifocal sporadic event in patients without an inherited syndrome or as a part of multiple endocrine neoplasia type 1. Key neuroglycopenic and hypoglycemic symptoms in conjunction with biochemical proof establish the diagnosis. Once the diagnosis is established, the insulinoma is preoperatively localized within the pancreas with the goal of surgical excision for cure. This review discusses the historical background, diagnosis, and management of sporadic insulinoma.

Fig. 1

Forty-eight hour fast. This patient has elevated serum insulin levels (>10 μU/mL) despite hypoglycemia indicating an insulinoma. (Courtesy of National Institutes of Health, Bethesda, MD).

Fig. 2

Lesion successfully localized by computed tomography scan. A round, well-circumscribed, hyperenhancing lesion can be seen at the tail of the pancreas (arrow). (Courtesy of National Institutes of Health, Bethesda, MD.)

Fig. 3

Left hepatic vein insulin concentrations after intra-arterial calcium injection. Injections of the superior mesenteric artery (SMA), gastroduodenal artery (GDA), and proper hepatic artery do not show any suspicious areas. However, the increase in insulin concentration after injection into the proximal and mid splenic arteries help localize this lesion to the tail of the pancreas. (Courtesy of National Institutes of Health, Bethesda, MD.)

Fig. 4

Right hepatic vein insulin concentration after intra-arterial calcium injection. Injections of the SMA, GDA, and proper hepatic artery do not show any suspicious areas. However, the increase in insulin concentration after injection into the proximal and mid splenic arteries helps to localize and confirm that this lesion is in the tail of the pancreas. (Courtesy of National Institutes of Health, Bethesda, MD.)

Fig. 5

Insulinoma enucleated from the tail of the pancreas. (Courtesy of Steven K. Libutti, MD, Bethesda, MD.)