[Diagnosis of ulcerative colitis and the biopsy method]

The biopsy specimen should be oriented flat on a ground glass slide or on a piece of filter paper so that the submucosa is on the slide and the mucosa uppermost to allow proper histopathological interpretation. It is important to perform the biopsy based on a full knowledge of features of inflammatory diseases of the large intestine. Biopsies should be taken from apparently normal and abnormal mucosa. It is necessary to observe the mucosa of the colon carefully for any mass lesions to find dysplasia or cancer complicating the ulcerative colitis. Any suspicious areas should be liberally biopsied. Biopsies should also be performed at random, because of possible existence of dysplasia or cancer which is not visible at endoscopy. This occurs especially in the rectum; biopsies can also be performed after inversion of the endoscope.