Criteria for predicting the outcome of pheochromocytoma by the immunohistochemical and electron microscopic findings.

Morphological examination of 22 functionally active adrenal pheochromocytomas was carried out. The content of catecholamine granules in tumor cells and in the number of sustentacular cells tended to decrease in metastasizing tumors. Electron microscopy showed two types of sustentacular cells and the possibility of their apoptotic death.

[Adrenocortical tumors with neuroendocrine differentiation]. / Adrenokortikal'nye opukholi s neiroéndokrinnoi differentsirovkoi.

18 adrenocortical tumours and 5 pheochromocytomas were studied immunohistochemically. Expression of synaptophysin and chromogranin A was found in cells of cortical adenomas, "frontier" neoplasms and in 20-75% of carcinoma cells, this ultramicroscopically was confirmed by observation of typical neuroendocrine granules. Some groups of cells of cortico-medullary tumours also expressed proteins of neural differentiation (protein S-100).

A chromogranin peptide is co-stored with insulin in the human pancreatic islet B-cell granules.

The immunoreaction of a rabbit chromogranin A and B antiserum was studied in normal human pancreatic islets. By examination of consecutive light microscopical sections, it was revealed that, at high antiserum concentrations (1:2000 or less), the whole islet area was heavily labelled, although the peripheral glucagon (A)-cells were the most intense in their immunoreaction. At low antiserum concentrations (1:4000 or more) the A-cells still showed the same intense labelling reaction, but the central B-cells were weakly labelled. Electron microscopically, reactivity towards the chromogranin A and B antiserum and the monoclonal insulin antibodies was present in the same central electron-dense core of the B-cell secretory granules, as demonstrated after application of the immunogold technique at different antibody dilutions. In the A-cells, the chromogranin immunoreactivity was concentrated at the peripheral mantle of the secretory granules. The D-cell granules showed a weak immunolabelling. Examination of human islets with the monoclonal chromogranin A antibody LK2H10 revealed immunogold labelling only in the peripheral mantle of the A-cell granules, while the B-cell granules were unlabelled. The present results show that a chromogranin peptide is co-stored with insulin the in normal human B-cell secretory granules. Although the exact composition of this B-cell chromogranin is unknown, it is not identical to that of the chromogranin A present in the A-cell granules.

Quantitative ultrastructure of endocrine cells of oxyntic mucosa in Zollinger-Ellison syndrome. Correspondence with light microscopic findings.

The endocrine cells of the oxyntic mucosa of five patients with longstanding Zollinger-Ellison syndrome were quantitatively investigated with electron microscopy and two light microscopic methods (Grimelius and immunostaining for chromogranin A). Ultrastructurally, the volume density of endocrine cells was 3.2% +/- 1.1% of the mucosal epithelial component, a 168% increase (P less than 0.001) over the value found in normal subjects. Of the six endocrine cell types of human oxyntic mucosa, only enterochromaffinlike cells increased in cell density (65% +/- 15% of the total endocrine cell mass), size, and number of cell profiles per unit area. The enterochromaffinlike cells also underwent morphological changes of secretory granules with a decrease in vacuolated forms, increase in elongated profiles, and appearance of granules with a punctate structure of the core. The latter variety of granules was previously observed only in carcinoid tumors of the oxyntic mucosa and is possibly related to the enterochromaffinlike cell hyperplasia-neoplasia sequence seen in hypergastrinemic patients. A positive relationship was found between endocrine cell densities evaluated ultrastructurally and with chromogranin A immunostaining. It is concluded that in Zollinger-Ellison syndrome, the trophic effects induced by longstanding hypergastrinemia are strictly selective for enterochromaffinlike cells and are associated with ultrastructural features typical for enterochromaffinlike cell tumors.