Villous adenoma of the duodenum: cellular composition and histochemical findings.

A villous adenoma of the duodenum was studied histologically and histochemically by semi-thin sections using glycol-methacrylate as embedding medium. All the four epithelial cell types which are present in normal duodenal mucosa (absorptive columnar, goblet, Paneth, endocrine) were found in the tumour, as well as undifferentiated elements. Neutral and acid non-sulphated mucins were detected. Cell type distribution and mucin production varied according to the degree of differentiation. Foci of gastric metaplasia were observed. A possible histogenesis from crypt base stem cell is considered.