QUANTITATIVE MORPHOLOGY OF COLLAGEN-FIBERS IN CUTANEOUS MALIGNANT-MELANOMA AND MELANOCYTIC NEVUS

Since tumor growth and metastastatic spread are considered to depend o n tumor-stroma interaction, the present study describes the architectu re of collagen fibers in 12 cases each of primary melanoma (vertical t umor thickness >1 mm) and common melanocytic nevi in azan-stained sect ions by using automated image analysis. In each case, at least 100 hig h-power fields were consecutively sampled from the tumor center, the t umor periphery, and the surrounding normal-appearing reticular dermis. In both diagnostic groups, collagen density (amount of collagen per t issue volume) and mean collagen fiber bundle diameter was significantl y lower in the tumor periphery than in the surrounding stroma End agai n lower in the tumor center than in the tumor periphery. When melanoma s and nevi were compared with each other, melanomas had fewer, but thi cker, collagen bundles than did nevi, particularly at the tumor periph ery. Taking the mean values of each case as classifiers in multivariat e logistic regression analysis, 21 of 24 cases were correctly classifi ed (chi-squared test, p < 0.0001), indicating that the parameters of c ollagen architecture at least in part reflect biological differences b etween benign and malignant melanocytic skin lesions.