[Myofibroblasts in the stroma of colonic tumors].

An ultrastructural examination of 18 colonic carcinomas detected myofibroblasts in 13 tumors. An inverse correlation was established between the level of myofibroblasts and the number of inflammatory cells. A multi-layered vascular basal membrane was found in the capillary vessels of 5 carcinomas. Myofibroblasts were invariably accompanied by altered smooth muscle cells corresponding to pericytes with smooth muscle traits. The findings suggest that myofibroblasts may develop from fibroblasts, smooth muscle cells of the intestinal wall and cells of vascular structures.