Scanning electron microscopy of Crohn's disease and ulcerative colitis of the colon

12 patients with Crohn's disease (CD) and 9 with ulcerative colitis (UC) affecting the colon were studied by scanning electron microscopy (SEM). The macroscopically unaffected mucosa was distorted in both diseases by irregularities in the normal polygonal units. The individual absorptive cells were disorganized, having lost their pentagonal-hexagonal cell borders. In 7 cases of CD an increase of goblet cells was seen. In 4 cases of UC their number was decreased. One case of UC showed an increased number of goblet cells, the case possibly belonging to the sub-category of indeterminate colitis. The microvilli were normal in CD but affected in many cells from cases of UC. Re-epithelization was followed during conservative treatment in 2 UC patients. It is suggested that with simplified SEM techniques the instrument can be a useful aid in the differential diagnosis of inflammatory colonic diseases.