Background: Adenomas are assumed to be the precursors of colorectal cancer. Aim was to study the epithelial and stromal components of various histological types of rectal adenomas. For evaluation of condition of all the components of neoplasia we have introduced a term “communicative systems” which consists of microcirculatory vessels and vegetative nerve terminals and the cell populations surrounding these two components.
Materials and Methods: A study of surgical and biopsy materials of tubular (TA), tubulovillous (TVA) and villous (VA) rectal adenomas — 30 cases of each histological type was performed. 20 biopsies of rectal mucosa were studied as a control group. The material was microscopically examined using Hematoxylin and Eosin, Picrofuchsin by van Gieson and immunohistochemical stains (Ki-67, CD31). Micromorphometric study was performed and nonparametric methods (U-Test, Kruskal-Wallis test) were used. Correlations were calculated using Spearman rank correlation coefficients. Probability values < 0.05 were considered significant.
Results: Index of proliferative activity of epithelial cells according to expression of Ki-67 in the control group comprised of 20.9±0.7, 26.6±0.3 in TA, 36.8±1.3 in TVA, 47.1±1.7 in VA. The reliable significant differences (p < 0.05) in proliferative activity of epithelial cells in the following adjacent pairs of tumors were revealed: TA–TVA, TVA–VA. Area of vascular bed was characterized by following indices: 30.7±0.9 in control group, 41.1±1.1 in TA, 82.2±1.3 in TVA, 274.3±7.3 in VA. The reliable significant differences (p < 0.05) in the intensity of vascularization in the following adjacent pairs of tumors were revealed: TA–TVA, TVA–VA. An increase in the following positions (p < 0.05) in the adjacent pairs is statistically reliable: epithelial cells and fibroblasts (control — TA), epithelial cells, plasma cells and fibrocytes (TA — TVA), epithelial cells, lymphocytes, plasma cells and polymorphonuclear leukocytes (TVA — VA). At the same time in the following sequence “normal mucosa N TA N TVA N VA” there is a gradual increase in the absolute number of all the studied cell populations. In the initial stages of tumor growth (TA), an increase in the number of correlations and activation of cell regulator such as macrophage, which along with fibroblast encloses the number of positive cell relations, is noted. In TVA, as the number of correlations decrease, the macrophage undergoes a peculiar isolation from other cells. In VA, for the first time, at the stages of tumor progression, the number of intercellular correlations reaches to minimum. Conclusion: A positive correlation between transitions from one morphological category to another exists with an evident increase in the absolute number of parenchymal and stromal cells. In the course of a tumor progression “normal mucosa N TA N TVA N VA” there is a gradual loss of correlations between cell elements of stroma that are isolated from each other. In a number of cases, according to the state of cellular infiltrate, degree of evident changes in the epithelial cells can be predicted. A full-value estimation of prognostic factors of rectal adenomas is possible only with a parallel study of parenchyma and stroma of the tumors.