PANCREATIC ACINAR CELL CLUSTERS IN PEDIATRIC GASTRIC-MUCOSA

Although clusters of pancreatic acinar cells (CPACs) have been reporte d in gastric mucosa of adults, they have not been described in childre n. We reviewed 283 pediatric gastric (239 antral and 44 corpus) mucosa l biopsies during a 2-year period and detected CPACs in 10 antral biop sy samples. These biopsy samples were stained immunohistochemically fo r pancreatic exocrine markers (trypsin, chymotrypsin, alpha-amylase, a nd lipase) and a panel of regulatory substances (insulin, glucagon, so matostatin, pancreatic polypeptide, gastrin, and serotonin). Double im munostaining for colocalization of chromogranins and trypsin as well a s mucin and trypsin also were performed on all cases. CPACs were seen in antral mucosa in a background of either normal or minimally inflame d mucosa, without any atrophy or metaplasia, and were positive for all pancreatic exocrine markers. Stray chromogranin-positive cells in the CPACs were also immunopositive for somatostatin, gastrin, or serotoni n. All CPACs showed a few hybrid (amphicrine) cells that coexpressed b oth chromogranin and trypsin. In one case, ultrastructural examination showed such cells to contain both zymogen and neurosecretory granules . Although the presence of CPACs exclusively in the antrum is most lik ely the result of a sampling bias, the presence of hybrid cells with a n amphicrine phenotype suggests that CPACs probably result from an abe rration of stem cell differentiation.