SCANNING ELECTRON-MICROSCOPIC STUDY OF THE COLLAGEN NETWORKS OF THE NORMAL MUCOSA, HYPERPLASTIC POLYPS, TUBULAR ADENOMA, AND ADENOCARCINOMAOF THE HUMAN LARGE-INTESTINE

The three-dimensional structure of the collagen network of normal muco sa, hyperplastic polyps, tubular adenoma, villous adenoma and adenocar cinoma of the human large intestine was examined by scanning electron microscopy after cell-maceration with a low temperature NaOH solution. In the normal large intestine, the surface of the sub-basal laminar c ollagen sheath lining the crypts was generally smooth. In hyperplastic polyps, the crypts extended and the sub-basal collagen network protru ded from the surrounding normal tissue. The sub-basal laminar collagen sheath was more densely arranged near the openings of the crypts and on the luminal surface than in deeper regions of the crypts. In tubula r adenoma, the tumor glands showed meandering, bending, and divisions. The sub-basal laminar collagen sheath was composed of densely packed collagen fibrils. In villous adenoma, the sub-basal laminar collagen s heath formed foliate or linguiform villous cores projecting sharply in to the lumen. In adenocarcinoma, the sub-basal laminar collagen sheath exhibited a dense arrangement of fibrils in the central region of the tumor. Toward the marginal region, the collagen sheaths surrounding t umor glands became thinner, and at the edge of the marginal region, ba sket-like collagen sheaths were observed around individual tumor cells infiltrating the interstitium. Such a tumor lesion was frequently sur rounded by a thick collagen fiber zone.