Chaperon normal goblet cells intercalated with dysplastic cells in duodenal adenomas express synaptophysin.

Background: Several authors demonstrated that normal goblet cells intermingle with dysplastic cells in duodenal adenomas. Goblet cells in the normal duodenum were found to cross-react with the neurotransmitter synaptophysin, a synaptic glycoprotein present in neuroendocrine cells and in virtually all neurons of the central nervous system. In this work, we investigated whether goblet cells in duodenal adenomas express synaptophysin. Materials and Methods: Sections from 29 duodenal adenomas were immunostained for synaptophysin. Results: All intercalated normal goblet cells in duodenal adenomas expressed synaptophysin. The mean percentage of synaptophysin-expressing goblet cells in the basal third of the adenomas was 49%, in the middle third 38% and in the superficial third 5% (basal and middle thirds vs. superficial third, p<0.05). Synaptophysin-positive goblet cells were also stained with alcian blue (pH 2.5) and MUC2, that stain sialomucins. In the normal ileum, only occasional goblet cells were stained (faintly) with synaptophysin. On the other hand, all goblet cells in the normal cecum were synaptophysin negative. Conclusion: Normal goblet cells found in duodenal adenomas express synaptophysin. Consequently, duodenal adenomas with synaptophysin-expressing goblet cells should also be stained with alcian blue (pH 2.5) or with MUC2 to confirm that these are native normal goblet cells, thereby rejecting the possibility of a composite adenoma-microcarcinoid in the duodenum.