Ultrastructural characterization of fundic endocrine cell hyperplasia associated with atrophic gastritis and hypergastrinaemia.

Clinical and experimental evidence indicates that carcinoid tumours of the stomach fundic mucosa represent another example of hormone-dependent neoplasm, gastrin being the hormone involved in tumour induction. In this context hyperplasia of fundic endocrine cells associated with chronic atrophic gastritis (CAG) and hypergastrinaemia is regarded as the most frequent preneoplastic lesion. However, the cell type involved in this hyperplasia has not been clarified. To elucidate this problem fundic endocrine cells were characterized ultrastructurally in 9 patients from which endoscopic gastric biopsies were obtained. ECL cells were the most frequent cell type in 8 cases, in 4 of which they were more numerous than all other cell types taken together. D1 cells were the most frequent type in one case while they were inconspicuous in the other cases. P cells were found with a frequency in each case intermediate between that of ECL cells and that of D1 cells. These results indicate that fundic endocrine cell hyperplasia occurring in hypergastrinaemic CAG is in most cases cytologically similar to that found in other hypergastrinemic conditions, in which the gastrin-dependent ECL cells were already found to prevail. They also explain why fundic carcinoids arising in CAG are mostly composed of ECL cells. The relation between ECL, D1 and P cells, if any, remains obscure.