Dermatology Practical & Conceptual

Reflectance confocal microscopy: a useful and non-invasive tool in the in vivo differentiation of benign pigmented skin lesions from malignant melanoma. Report of a case. Copyright: ©2013 Hofmann-Wellenhof et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. A 67-year-old man was referred to our department because of a pigmented skin lesion that was clinically suspicious for melanoma. The patient presented with several pigmented skin lesions on the back. He reported that they had been present for a few years and that he had noticed a change in color and slow enlargement in one pigmented skin lesion on his right shoulder. Clinically, there was a light-to-dark brown patch approximately 1.5 cm in diameter. Dermoscopy showed a light-to-dark brown homogenous-reticular pattern with focal gray-brown to gray-white areas (Figure 1A). The clinical and dermoscopic features were most suggestive of a solar lentigo / early seborrheic keratosis (SK) with regression, but a mel-anoma on sun-damaged skin or a collision of a melanoma with an SK were considered in the differential diagnosis. With reflectance confocal microscopy (RCM), a slightly atypical honeycomb pattern was seen at the superficial epidermal layers. At the basal layer, multiple densely packed edged papil-lae of different sizes and shapes were observed (Figure 1B). The diagnosis of seborrheic keratoses (SK) undergoing regression can be challenging clinically and der-moscopically. We report a case of a SK with a history of change and equivocal dermoscopic features, thereby showing confocal features suggestive of solar lentigo/early SK. The present case emphasizes the potential value of reflectance confocal microscopy (RCM) in the differentiation of malignant from benign pigmented skin lesions.