[Combined ultrastructural and immunocytochemical studies of pancreatic endocrine tumors].

9 surgically removed endocrine tumours of pancreas of female patients aged from 19 to 71 years were studied. The material was stained with hematoxylin and eosin, by Grimelius and Fontana--Masson; PAP method with polyclonal antibodies to insulin, glucagon and somatostatin was also used. Immunoreactivity was weaker in tumours with clinically pronounced hormonal activity as compared to the normal endocrine cells in the Langerhans islets. This is confirmed ultrastructurally: tumour cells contain comparatively low number of neuroendocrine granules. Functionally inactive tumours show the opposite immunohistochemical results. The multipotential properties of cells forming pancreatic endocrine tumours are discussed.