Do stem cells participate in cell turnover in duodenal adenomas? A preliminary study on Paneth cells.

BACKGROUND In the normal duodenum, Paneth cells migrate from the stem cells downwards, towards the bottom of the crypts of Lieberkuhn. MATERIALS AND METHODS The spatial position of Paneth cells within the profile of histological sections was investigated with hematoxilin and eosin (H&E) in 6 duodenal adenomas; 2 of them were also immonostained with lysozyme, an enzyme present in Paneth cells. RESULTS In H&E stain sections, the numbers of mature Paneth cells/high power field varied from 2 to 7 (mean 4.5). In the two immunostained adenomas, the numbers of lysozyme-expressing cells/high power field were 15 and 42, respectively. The lysozyme-stained cells were present at all levels in the adenomas, including the luminal epithelial layer. CONCLUSION In duodenal adenomas, not all Paneth cells detected by lysozyme immunostain are apparent in H&E-stained sections, suggesting that lysozyme immunostain also detects Paneth cells precursors. Since mature Paneth cells and their precursors are positioned underneath the stem cells, it is conceivable that the Paneth cells that had reached the luminal aspect of the adenomas, were preceded by stem cells. This possibility would imply that in duodenal adenomas, the stem cells would be subjected to the same laws that orchestrate the turnover of epithelial duodenal cells, including Paneth cells and their precursors.