Scanning electron microscopic study of the three-dimensional structure of the collagen networks of gastric cancer.

The three-dimensional structure of the collagen networks in human gastric carcinoma was examined by scanning electron microscopy (SEM) after treatment with the cell-maceration method using a low temperature NaOH solution. Based on stromal content, the poorly differentiated adenocarcinoma can be divided into the medullary carcinoma area and the scirrhous carcinoma area. In the medullary carcinoma, the collagen sheath around the small tumor cell acinus formed spherical chambers (20-30 microns in diameter) with fenestrations (about 5 microns in diameter) connecting the chambers. The collagen sheath was composed of fine collagen fibrils (about 50 nm in diameter). In the scirrhous area, there was abundant fibrous stroma composed of thicker collagen fibrils (about 100 nm in diameter). Tiny tumor cell nests were sporadically seen in the fibrous stroma. These tumor nests were surrounded by collagen fibrils (about 50 nm in diameter). In the moderately differentiated tubular adenocarcinoma, the tumors were surrounded by spherical, ovoid or irregular shaped thick collagen sheaths (50-200 microns in diameter), which were composed of loosely packed 50 nm collagen fibrils. In well differentiated tubular adenocarcinoma, tumor glands were surrounded by spherical, ovoid or irregularly-shaped thick collagen sheaths (50-200 microns in diameter), composed of densely arranged fine collagen fibrils. In papillary carcinoma, the collagen sheaths were nipple-shaped. They were composed of very densely arranged fine collagen fibrils (about 50 nm in diameter).