Studies on schistosomal rectal and colonic polyposis.

Anatomic and digestion studies were done on rectal and colonic schistosomal polyps from 30 patients. Results indicate that schistosomal colonic polyposis is principally due to high, localized egg burdens of Schistosoma mansoni or S. haematobium resulting in damage to the muscularis mucosa of the colon. Furthermore, atypically focal oviposition by S. mansoni is probably more important in genesis of rectocolonic polyposis than is schistosomiasis haematobium.