Clinical pathology of endocrine tumors of the pancreas. Analysis of autopsy cases.

A clinicopathological analysis of endocrine tumors of the pancreas, using 800 autopsy cases (422 men, 378 women, mean age 78.7) was accomplished. The results were: (1) Endocrine tumors and similar lesions were found in 3% or 24 cases (25 lesions). Twenty lesions (20 cases) were found to be tumors and five lesions (five cases) were determined to be hyperplasia of Langerhans islets. (2) Incidence of tumor was 10% (6/60) in individuals having histological studies of all sections of the pancreas, and 1.6% (12/738) in individuals having histological studies of three random sections of the pancreas. (3) None of the cases with tumors and hyperplastic lesions showed symptoms of hormone production. (4) Immunohistochemical analysis revealed hormone production in all 20 tumor cases and multiple hormone production was found in 14 of these (70%). (5) Ductular or tubular structures were found in or adjacent to the tumors in 12 cases (60%) and hyperplasia in one case (20%). Langerhans islets, 500 microns or larger in size, were found in three lesions of the tumor (15%). Langerhans islets with the mean diameter of normal islets + 2 SD or larger also were found around five tumors (25%) and three hyperplasias (60%). The above findings suggest that endocrine tumors of the pancreas are prevalent and that they do not produce symptoms of excessive hormone production even though they do continue to produce hormones. Some of the endocrine tumors or hyperplasias develop from totipotent stem cells of the duct epithelia, and factors promoting the growth of Langerhans islets might exist.