Juvenile and adenomatous gastrointestinal polyposis.

This is the fourth report of a case showing an association between juvenile and adenomatous polyposis. Starting at age 14, this patient underwent multiple polypectomies and gastrointestinal resections over a 15-year period. Although initial biopsies were diagnosed as juvenile polyps, later biopsies showed both adenomatous polyps and large polypoid masses with a mixture of juvenile and adenomatous features. Several typical small hyperplastic polyps were also found in the stomach. This case contrasts with the previous three cases in that the gastrointestinal tract is more widely involved and in that there is an unusual marked hyperplasia of argentaffin- and argyrophil-positive cells. The case reported here strengthens the relation between adenomatous polyposis and juvenile polyposis.