Morphometric, DNA, and proliferating cell nuclear antigen measurements in benign melanocytic lesions and cutaneous malignant melanoma.

Morphometric, DNA, and proliferating cell nuclear antigen (PCNA) measurements were taken of benign melanocytic tumors and malignant melanomas. Significant differences between lesion groups according to Krushell-Wallis analysis were found in terms of mean nuclear area, coefficient of variation (cv) of nuclear area, cv of nuclear shape nuclear contour index (NCI), mean and cv of nucleolar area, DNA 2.5 c and 5 c exceeding rates, and PCNA positivity. A logistic regression analysis with respect to banal nevi versus primary malignant melanoma showed that the cv of nuclear area and the DNA 2.5 c exceeding rate were significant independent predictors. Nuclear polymorphism, i.e., the cv of nuclear shape NCI, was larger in metastasizing primary melanomas than in thin nonmetastasizing primary melanomas. PCNA positivity was occasionally increased in keratinocytes adjacent to nevi or melanomas. Larger values for nuclear area, DNA aneuploidy, and PCNA positivity were found in thick malignant melanomas and melanoma metastases than in benign melanocytic lesions and thin malignant melanomas. Morphometry, DNA content, and PCNA positivity thus seem to reflect different stages in tumor progression of malignant melanoma.