Dermoscopy

First, a brief introduction about types of dermoscope and an explanation on the theory of dermoscopy are provided. Second, some introduction on the difference of dermoscopic pictures between benign and malignant neoplasm is given. Basically, benign lesions tend to show symmetrical dermoscopic structures and colors, whereas malignant lesions have a tendency to present irregular and atypical dermoscopic structures. Third, the relationship between dermoscopic images and anatomical structures will be shown. Acral melanocytic lesions have site-specific dermoscopic patterns, namely parallel furrow pattern or parallel ridge pattern. These parallel patterns are due to different distribution of benign and malignant melanocytes. Benign melanocytes (nevus cells) are mainly found on the tips of crista profunda limitans and supply melanin granules to the furrows of stratum corneum, making a parallel furrow pattern. To the contrary, melanoma cells proliferate mainly on the tips of crista profunda intermedia or rather diffusely and randomly, and supply melanin granules irregularly and diffusely to the ridges of stratum corneum, having parallel ridge pattern. Fourth, the global features of dermoscopic findings are described respectively with definitions of the technical terms. To analyze dermoscopic structures, it is easier to look at global features first and local features next. Basic global features include reticular, globular, cobblestone, homogeneous, starburst and parallel patterns. If a given dermoscopy image has two patterns, the more prominent pattern might be chosen. If it has more than three dermoscopic patterns, then multi-component pattern is the reasonable selection. If there are no particular dermoscopic structures, then the unspecific pattern will be selected. Finally, some comments on the relationship between dermoscopy and dermatopathology are given briefly. It is always useful to imagine dermatopathological features when examining a dermoscopic image. There are considerable relations between dermoscopy and dermatopathology.