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The nucleolar organizer regions (AgNORs) have been studied by video image analysis in the normal colorectum and in adenomas arising there. Total AgNOR area was measured in conjunction with the total area of nuclei and expressed as a ratio. AgNORs are found to predominate in the proliferative regions of the normal mucosal crypt, and the ratio of AgNOR to nuclear area proved significantly greater in the normal colon than in the rectum and far greater in colorectal adenomas. Further, there is a significant difference between the ratio in tubular as opposed to villous patterns of adenomatous growth in the colon but not in the rectum. When classified according to their degree of dysplasia, adenomas in the rectum exhibit a significantly higher ratio of AgNOR to nuclear area as the degree of dysplasia increases in severity. This correlation is not shown in the colon.

The differentiation between Spitz naevus and melanoma is at times difficult. The present study was undertaken to define means to positively identify such melanocytic tumours of doubtful malignancy. Immunohistochemical staining intensity for S100 protein and neurone specific enolase (NSE) was measured in sections of 35 Spitz naevi using a microcomputer image analysis system. The data were compared with results previously obtained from 19 cases of malignant melanoma and 16 benign compound naevi. Disaggregated cells from paraffin-embedded material were stained by the Feulgen technique for DNA estimation. The nuclear DNA content distributions were measured using the same image analysis system. Compared with the malignant cases, the Spitz naevi showed significantly lower staining intensity for both S100 protein (P less than 0.0001) and NSE (P less than 0.0001). When compared with the benign compound naevi, the staining intensity was significantly lower for S100 protein (P = 0.003). The nuclear DNA distribution in Spitz naevi proved to be a normal diploid pattern in 31 cases. Four cases showed a small proportion of hyperdiploid nuclei. The results show that Spitz naevi can be significantly distinguished from malignant melanoma by staining intensity for S100 protein and NSE. A normal diploid DNA content distribution appears to be typical for Spitz naevi. Spitz and benign compound naevi show dissimilar expression of S100 protein which may indicate different patterns of differentiation in these two types of lesion. The image analysis equipment used in this study is accurate, simple to use, produces results rapidly, and is economic. Therefore, it is clinically practicable.

The grading of gastric epithelial dysplasia has been studied by means of computer aided morphometry. Measurements of histological features were made on segments of epithelium from 38 selected cases of dysplasia graded by subjective assessment. The measurements were statistically compared with the subjective scores using discriminant analysis. The measurements were found to provide significant discrimination between all groups. Nuclear size proved to be the main discriminating variable. Prediction of the likely group membership of individual cases was possible using classification equations derived from the discriminant analysis. Classification of the original data set revealed prediction errors which suggested a bias against diagnosis of dysplasia. As a result of this study reliable, repeatable and objective gradings of gastric epithelial dysplasia can be obtained by inexperienced persons with an accuracy approaching that of a skilled pathologist.

Recently, several flow cytometric studies have shown that the nuclear DNA content in colorectal carcinoma gives prognostic information which is independent of that provided by the histological characteristics of the tumour. In this study the nuclear DNA content and nuclear morphology of 39 cases of surgically resected rectal adenocarcinoma were measured in Feulgen-stained histological sections by video image analysis and 97 per cent were aneuploid. Dukes' stage correlated better with the morphometric data than did other classification systems. The extent of local spread and the growth pattern at the invasive margin of the tumour, which are of known prognostic importance, were significantly related to some nuclear features. Discriminant analysis of the nuclear morphometric data alone was highly successful in predicting these tumour characteristics. The results suggest that routine application of this technique to tumour biopsies may be of value in patient management since it provides stage-related information which cannot be obtained by conventional histopathological assessment.

Tumour cells and macrophages are thought to interact and the behaviour of tumours may be modified by macrophage activity. Using an immuno-histochemical method for the demonstration of lysozyme and a computerised image analysis system, the number of macrophages was assessed in and around tubulovillous adenomas and the different Dukes grades of adenocarcinomas of the colon. No significant differences were demonstrated and it is concluded that the behaviour of these neoplasms is not related to the number of associated macrophages.