Method for the quantitative evaluation of the distribution pattern of nuclei in normal and malignant endometrial epithelia.

A quantitative method of evaluating the pattern of distribution of nuclei within a cell cluster was developed and applied to endometrial cytology. The distribution pattern (DP) is mathematically expressed using a "DP index," which can be determined as a product of the square root of the nuclear density, square root of n0, and the mean distance between the two nearest nuclei, r. The DP index has a limited range of decreasing values from 1.074 to 0.5 to 0, indicative of regular, random and aggregated patterns of nuclear distribution, respectively. The estimated DP index was 0.831 +/- 0.031 (mean +/- standard deviation) in the clusters of normal endometrial epithelial cells from 16 nonneoplastic cases, but 0.638 +/- 0.041 in malignant epithelia from 19 cases of well-differentiated adenocarcinoma. The index of normal epithelia was close to 0.877 of the regular hexagonal distribution pattern. Contrary to this, the DP index was significantly smaller in well-differentiated adenocarcinoma (P less than .001), approaching 0.5, the theoretical value of a random distribution pattern. These findings suggest that quantitative analysis of the distribution pattern of nuclei can be a useful aid in the cytodiagnosis of endometrial lesions.