Islet cell tumors are uncommon neoplasms of neuroendocrine origin arising in the pancreas or the peri-ampullary region. Despite their rarity, with a reported incidence of five cases per million persons per year [1], they present a special challenge for the radiologist. The diagnosis of functioning islet cell tumors is almost always established biochemically when the lesion is of small size. Successful curative surgical resection is facilitated by preoperative imaging depicting the precise location and number of lesions. Patients with nonfunctioning islet cell tumors often present with the disease at an ad-
vanced stage. Imaging plays a pivotal role in differentiating these tumors from adenocarci-nomas of the pancreas and in identifying signs of malignancy.
Although in recent years gadolinium-enhanced MR imaging, somatostatin-receptor imaging, and endosonography have emerged as potentially competing or complementary techniques to CT, dual-phase helical CT, particularly with technical improvements afforded by multidetector CT, remains the dominant imaging modality for the diagnosis of all pancreatic neoplasms, including, in many centers, islet cell tumors. The objectives of our pictorial essay are
to illustrate the various imaging features of islet cell tumors on dual-phase CT and to discuss potential pitfalls.
