NEUROENDOCRINE TUMORS OF THE GASTROENTEROPANCREATIC SYSTEM .1. DIAGNOSTIC ADVANCES

Neuroendocrine tumors of the gastroenteropancreatic system present bot h a diagnostic and therapeutic challenge. Even in a patient presenting with a clinical hypersecretion syndrome such as the carcinoid syndrom e, the Zollinger-Ellison syndrome or the hypoglycemia syndrome the pri mary tumor is often difficult to localize. Recently, tumor imaging has been improved by two new powerful techniques, the endosonography and the somatostatin-receptor scintigraphy. In addition, the new arterial secretin or calcium injection tests may guide surgery in patients with gastrinoma or insulinoma, respectively. The recently introduced posit ron emission tomography with C-11-5-hydroxytryptophan can provide info rmation about biochemical and metabolic changes in neuroendocrine tumo rs. Patients with the hereditary form of neuroendocrine tumor disease of the foregut suffer from the multiple endocrine neoplasia type 1 syn drome. The genetic defect of this autosomal dominant disease has been assigned to chromosomal region 11q13. Current investigations aim to de tect the multiple endocrine neoplasia 1 gene and thus to allow early d iagnosis of hereditary neuroendocrine tumor disease of the foregut.