COMMON ACQUIRED MELANOCYTIC NEVI, DYSPLASTIC MELANOCYTIC NEVI AND MALIGNANT MELANOMAS - AN IMAGE-ANALYSIS CYTOMETRIC STUDY

We used computerized image analysis cytometry to analyze 10 melanocyti c lesions from each of the following categories: common acquired nevi, melanocytic nevi with architectural features of dysplasia, dysplastic melanocytic nevi (DMN) with slight atypia, DMN with moderate atypia, DMN with severe atypia, and superficial spreading melanomas. The nucle i of at least 50 consecutive nevomelanocytes in the most atypical zone s were digitized at X1000 under oil immersion, without knowledge of di agnosis by one observer. Grading of atypia was based on current practi ces as described in the literature, The results showed significant dif ferences (p < 0.05) in nuclear area and standard deviation of nuclear area between melanoma and DMN with severe atypia, and between DMN with severe atypia and all other categories of nevi. There were no differe nces among any lesions with respect to nuclear shape. No differences i n nuclear area were found among DMN with moderate, or slight atypia, n evi with features of dysplasia, and typical nevi. These results show f or the first time objective distinction of low-grade (slight-moderate atypia), and high-grade or severe atypia in pre-malignant nevomelanocy tic lesions of the skin.