Gastrinomas and insulinomas are the two most common pancreatic endocrine tumors. This review focuses predominantly on the different diagnostic tools available to the clinician and the relative merits of each modality. The sensitivities of computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, endoscopic ultrasound, and angiography with venous sampling for diagnosing islet cell tumors are compared. A diagnostic algorithm for the management of these tumors is provided at the end of the discussion. Tumors arising from the pancreatic islet cells are rare and represent a heterogeneous group of benign or malignant lesions.
Most tumors present with well characterized syndromes, whereas others appear to be nonfunctioning.
The clinical features of 11 men and 7 women with nonfunctioning islet cell carcinomas operated on between 1983 and 1998 were reviewed. Gut hormone profiles were normal in all patients. Abdominal sonography and computed tomography localized the tumor in 17 patients, and correct prediction of an endocrine tumor was achieved in 12 patients. Six of seven patients showed a hypervascular tumor upon angiography, and seven of eight patients preoperatively had positive somatostatin receptor scintigraphy. Three patients had up to three more resection for metastases.