Value of a single forceps biopsy of colonic polyps.

The accuracy of colonoscopic biopsies in predicting the histological diagnosis of colonic polyps removed at colonoscopy or at laparotomy was studied. Forty-two patients were colonoscoped before the removal of 50 polyps. A single fractional biopsy was obtained from each lesion with the standard endoscopic biopsy forceps and was compared to the final histological diagnosis of each excised lesion. Thirteen (26%) of the singular fractional biopsies did not demonstrate the significant histological features of the excised polyps. These tiny biopsies do not adequately represent the entire polyp. Moreover, the 2- to 3-mm size of the biopsy does not permit the study of the central submucosal area of the polyp stalk, the critical area for assessing invasive malignancy. Histological examination of a completely excised polyp is essential for accurate diagnosis and appropriate therapy.