[Histopathology of ulcerative colitis in biopsy]

For histologic diagnosis on biopsy specimens, we gave an outline of macroscopic and microscopic features of ulcerative colitis (UC), including differential diagnosis. The most important histologic features on biopsy are dense mixed inflammatory infiltrate in the lamina propria mucosae, mucosal architectural abnormality, and vascular change. Evidence of colorectal adenocarcinoma, dysplasia, and cytomegalovirus infection should also be taken into account. Although diagnostic criteria for UC are well understood, the biopsy diagnosis of UC is comparatively difficult. Thus the diagnosis of UC should be made mainly by clinical pictures, course of the illness, and radiological and endoscopic pictures.