Inject the specimen with formalin. Evacuate gross fecal contents by gentle external massage of the specimen. One end of the specimen is tied off, the specimen is injected with formalin, and the other end is tied off. If a constricting lesion is present, be sure that adequate fixative can be easily passed through the point of constriction.
Injection is especially demonstrative in cases of diverticulosis.
Take two Polaroid photographs and identify in one of them the sites of the sections to be taken. In general, take the sections perpendicular to the direction of the mucosal folds. For ulcerative colitis it is imperative to exclude carcinoma both by sectioning all unusual areas as well as examination of the lymph nodes. Dysplastic changes are of importance, particularly if the rectum has been left in place. Two options are available to study the bowel, depending on the size and location of the tumor and the status of the specimen when received in the laboratory Open the bowel longitudinally through its entire length, trying not to cut through the tumor.