Morphometric, DNA and PCNA in thin malignant melanomas.

Morphometric assessment of nuclear area, shape and density, nucleolar area, analysis of DNA content and expression of proliferating cell nuclear antigen (PCNA) was performed in a case control study of 72 malignant melanomas, thickness < or = 0.8 mm and Clark level II-III. Twenty-four thin metastasizing melanomas (TMM) were individually compared to two thin non-metastasizing melanomas (TNM) after individual matching for site of primary tumor, tumor thickness, level of invasion, tumor regression and duration of follow-up. Conditional logistic regression analysis with maximum likelihood estimates showed significant differences between TMM and TNM with regard to the nuclear correlation coefficient (p = 0.005), standard deviation of nuclear shape NCI (p = 0.017), and nuclear density (p = 0.030), indicating that thin melanomas with pleomorphic and possibly densely packed nuclei are associated with recurrence. No significant differences were found regarding nuclear or nucleolar area, mean nuclear shape NCI, nuclear DNA content or expression of PCNA.