A NEW ASPECT OF GASTRIC METAPLASIA IN CROHNS-DISEASE - BIDIRECTIONAL (FOVEOLAR AND PYLORIC) DIFFERENTIATION IN SO-CALLED PYLORIC METAPLASIAIN THE ILEUM

Mucus-secreting cells found at the site of ileac ulceration in Crohn's disease have been described as 'pyloric metaplasia'. Using mucin-hist ochemical methods and immunohistochemical stainings for Ki-67 antigen and foveolar-type mucin (M1) of the stomach, the characteristics of th is type of metaplasia were studied in surgically resected ileac specim ens from two Japanese patients with Crohn's disease. Not only pyloric- type cells but also foveolar-type cells were demonstrated; often displ aying an organoid growth of the normal stomach mucosa. Stem cells of t he ileac crypt may differentiate potentially to intestinal-, pyloric- and also to foveolar-type cells. The term 'pyloric metaplasia' is not appropriate and 'gastric metaplasia' should be used when describing th is type of metaplasia.