Dermoscopy for acral pigmented skin lesions

Abstract

Acral volar skin is the most prevalent site of malignant melanoma in nonwhite populations. In Japanese, about one half of all cutaneous melanomas are seen on acral skin, and nearly 30% of melanomas affect the sole of the foot.1,2 The rate of acral melanoma is much higher in blacks. Moreover, the incidence and real number of malignant melanoma affecting the acral skin were reported to be almost the same among all races, the incidence being 0.3/100,000 populations per year.3,4 In any race, therefore, early detection and accurate diagnosis of malignant melanoma on acral skin are very important to improve the prognosis. On acral skin, melanocytic nevi are also frequently found. In our data, 8% of Japanese have melanocytic nevi on their soles.1 In addition, we sometimes encounter nonmelanocytic pigmented lesions on acral skin, such as the so-called black heel, which may produce problems in clinical differentiation from early melanoma. In this article, we describe characteristic dermoscopic features of various kinds of pigmented lesions on acral skin and emphasize the diagnostic value of the parallelridge pattern in diagnosing early melanoma at this anatomic site. Using this dermoscopic criterion, we detected several cases of early melanoma in situ, which were difficult to be diagnosed clinically and/or histopathologically.