Correlation between epiluminescence microscopy characteristics of malignant melanomas and Clark's level of invasion

Many epiluminescence microscopy (ELM) characteristics of malignant melanoma support the differential diagnosis of pigmented skin tumors. A preinvasive evaluation of level of invasion would be valuable for planning the excisio n margins. Since sonography for tumor thickness measurement is rarely avail able in a practice we searched for specific ELM criteria correlating with C lark's lebel of invasion. In our retrospective study of 120 malignant melan omas of 30 ELM features were studied for their correlation and the associat ion was significant for 15 features. The following criteria were found only in level Ill-IV melanomas: intralesional horizontally elongated blood vess els,spontaneous microhemorrhages, plaster-of-Paris-like lacunae, grey-blue/ yellowish-brown/reddish saccular pattern and eccentric nodes (reddish, livi d, blue). 7 characteristics were predominantly found in level III-IV melano mas and seldom in "thin" melanomas (level I-II):deeply localized gray-blue/ -brown fragmentary network,whitish-opaque septa, whitish- or bluish-opaque veil, negative pigmented network, areola with evenly arranged capillaries, polymorphic capillaries. Perivascular melanophages, eccentric dark blotches , pseudotrabeculae of melanophages and greyish-blue:annular perifollicular pigmentations were the most significant association of ELM criteria in "thi n" melanomas (level I-II). Epiluminescence microscopy is not only a tool fo r the differentiation of melanocytic lesions but also for a preinvasive eva luation of Clark's level of invasion.