Multiple juvenile polyposis. A study of the pathogenesis of juvenile polyps and their relationship to colonic adenomas.

Solitary juvenile polyps are common lesions whose pathogenesis is poorly understood. Multiple juvenile polyposis is characterized by large numbers of these lesions either confined to the colon or throughout the gastrointestinal tract. A study of two cases of multiple juvenile polyposis provided fresh insight into the pathogenesis of juvenile polyps and their relationship to colonic adenomas. Mucosal ulceration in very early lesions, together with glandular epithelial calcification, suggested that impaired cell renewal resulting from disturbed regenerative kinetics may predispose to surface epithelial erosion, setting in motion a cycle of ulceration, inflammation, and granulation tissue formation. We postulate that a dyskinetic continuum may link juvenile, "metaplastic," and adenomatous polyps. The finding in our second case of multiple adenomatous lesions, including a villoglandular polyp, emphasizes the neoplastic potential of juvenile polyposis.