[Epiluminescence microscopic characteristics of small malignant melanoma]

17% of malignant melanomas (n = 100) investigated in a dermatologic practice were less than 6 mm in maximal diameter (median diameter: 4.0 +/- 0.9 mm). The median age of the 17 patients at diagnosis of small-diameter melanomas was 42 years. The essential epiluminescence microscopic and histopathologic features of these small melanomas resembled those of larger lesions, although their clinical criteria differed from the classic ABCDs.6 (35.3%) of the small melanomas were were found to be in situ. This percentage was nearly similar to those in situ lesions within the group of melanomas of 6 mm in diameter or larger (38.3%). The remaining 11 small lesions were classified as invasive from Clark's level I to V, including all classic histogenetic types (superficial spreading, nodular, unclassified, desmoplastic). The median thickness of the small invasive melanomas was 0.76 +/- 0.23 mm. 7 small melanomas had apparent histologic remnants of a melanocytic nevus. Epiluminescence microscopic features of the melanomas were evaluated and statistically compared with those of 100 dysplastic nevi and 50 spindle cell nevi. The technique of epiluminescence microscopy allowed the identification of such malignant melanomas that could not be discerned by the naked eye or by a pocket-lens.