Rectal bleeding due to amebic colitis diagnosed by multiple endoscopic biopsies: report of two cases.

Recurrent rectal bleeding over a period of seven and 12 months, respectively, was the main and unusual manifestation of amebic colitis in two patients. The difficulty in establishing the diagnosis led to one patient's receiving potentially dangerous steroid therapy. Only by taking multiple colonoscopic biopsies was the amebic colitis recognized. This and serologic tests, should be routine in all cases of inflammatory bowel disease before initiating therapy.