Figure 3. (a) On pathology, the colon shows a markedly thickened and fibrous serosal membrane (S) and disappearance of the outer longitudinal muscle layer (haematoxylin–eosin stain x 40). (b) On special stain for fibrous tissue, the colon shows a markedly thickened and fibrous serosal membrane (S) (Masson-trichrom stain x 40).