Stereological assessment of architectural changes in dysplastic epithelium of colorectal adenomas

Against the background of developing quantitative prognostic indicators for the future risk of colorectal cancer in adenoma bearing-patients, the possibilities of stereological measuring techniques for providing objective measures of architectural changes in colorectal adenomas were examined.

The haematoxylin-eosin stained tissue sections of 59 adenomas, of which 20 showed mild dysplasia, 20 moderate dysplasis, and 19 severe dysplasia, were assessed. Using a projection microscope equipped with a coherent test system that was specifically designed to analyze anisotropic tissue, the volume density of stroma, epithelium and lumen, the outer and the inner gland surface density, and the length density lumen were determined.

With respect to grading, significant differences in the means of the inner gland surface density and the length density lumen were found mainly between mild and severe dysplasia as well as between moderate and severe dysplasia. This was especially evident when considering the subgroup of tubular adenomas. Stepwise discriminant analysis resulted in an overall correct jackknifed classification of 81.3% when mild and moderate dysplasia cases were taken as one group, and were compared with the group of severe dysplasia cases. With respect to histological type, the volume density lumen and the outer surface density glands, were most favourable. These two features allowed for an 87.5% overall correct jackknifed classification of tubular adenomas, versus adenomas with villous components. The analysis time was roughly 30 minutes per polyp. Intra-observer reproducibility was satisfying, with CE-values < or = 5% for all variables. Inter-observer reproducibility tests were encouraging.

The application of stereological techniques can be worthwhile in assisting in the classification of colorectal adenomatous polyps. Such techniques could therefore be a useful tool to estimate the prognostic value of adenoma morphology with respect to the development of metachronous colorectal tumours.