Evidence of Hormonal, Laboratory, Biochemical, and Instrumental Diagnostics of Endocrine Tumors of the Pancreas

Abstract

Pancreatic endocrine tumors secrete inappropriately high levels of specific endocrine hormones, as well as peptides such as chromogranin A, pancreatic polypeptide, and synaptophysin. Strict conditions of measurement are necessary as these hormones and peptides are proteolyzed rapidly, may be secreted episodically, and are affected by commonly used drugs. Tumors may secrete variants of the hormone not measureable by commercially available assays. In patients with multiple endocrine neoplasia syndrome type 1 (MEN-1), gene sequencing is not recommended at the moment, but it may eventually be useful. Asymptomatic patients require monitoring for pancreatic endocrine tumors by regular screening of hormones. After biochemical confirmation of the diagnosis, localization may be difficult in some small tumors. Conventional imaging techniques are useful but, as these tumors express cell-surface somatostatin receptors (SSTRs), advances in the use of specialized SSTR-linked radionuclide scanning have improved their localization greatly. However, these are expensive and may not be generally available.