Characteristic Epiluminescent Microscopic Features of Early Malignant Melanoma on Glabrous Skin: A Videomicroscopic Analysis

Objective To investigate the characteristic epiluminescent microscopic features of early lesions of malignant melanoma affecting glabrous skin, which is the most prevalent site of the neoplasm in nonwhite populations. Design The epiluminescent microscopic features of various kinds of melanocytic lesions affecting glabrous skin were investigated using a videomicroscope. All the diagnoses were determined clinically and histopathologically using the standard criteria. Setting A dermatology clinic at a university hospital. Patients The following 130 melanocytic lesions consecutively diagnosed at our department were examined: 16 lesions of acral lentiginous melanoma, 6 lesions of malignant melanoma in situ, and 108 lesions of benign melanocytic nevus (acquired or congenital). Main Outcome Measure The incidence of each characteristic epiluminescent feature was compared among disease categories. Results On epiluminescent microscopy, malignant melanoma in situ and the macular portions of invasive malignant melanoma showed accentuated pigmentation on the ridges of the skin markings, which are arranged in parallel patterns on glabrous skin. This "parallel ridge pattern" was found in 5 (83%) of 6 lesions of malignant melanoma in situ and in 15 (94%) of 16 lesions of malignant melanoma. The parallel ridge pattern was rarely found in the lesions of benign melanocytic nevus. Most benign melanocytic nevi showed 1 of the following 3 typical epiluminescent patterns: (1) a parallel furrow pattern exhibiting pigmentation on the parallel sulci of the skin markings (54%), (2) a latticelike pattern (21%), and (3) a fibrillar pattern showing filamentous or meshlike pigmentation (15%). The remaining 11 benign nevi (10%) showed a nontypical pattern. Conclusion Because epiluminescent microscopic features of early malignant melanoma on glabrous skin are characteristic, we can effectively detect early lesions using this noninvasive method.