Endocrine pancreatic tumors.

The pathology and cell biology of endocrine pancreatic tumors are reviewed. It is probable that all these tumors are "functioning" in the sense that they elaborate hormones that cause more or less conspicuous clinical syndromes. Identification of such secretory products is essential for an optimal diagnosis, localization, treatment, and follow-up. Recent data indicate that endocrine pancreatic tumors evolve from progenitor cells of ducts. This histogenetic mechanism may explain the occurrence not only of mixed or multihormonal tumors but also of tumors producing hormones that are absent from the adult human pancreas. In addition to their clinically apparent effects, many endocrine pancreatic tumors affect the surrounding endocrine pancreas in a characteristic way. The mechanisms behind and the potential diagnostic usefulness of these changes are discussed.