Dr. Kirby presented a valuable discussion on dermoscopy Friday morning of SDPA Digital. She began by breaking down the normal colors found in the skin. For example, black is the result of melanin in the stratum corneum and may be a result of the movement of melanocytes from the dermo-epidermal junction as they move up to the epidermis such as in pagetoid spread with melanoma. On the other hand, as melanin moves deeper into the dermis, the appearance can be grey revealing depth to the papillary dermis, and blue with depth into the reticular dermis.
Dermoscopic features correlate with histologic features and as such can be reassuring or concerning revealing the need for biopsy in clinical practice. Dr. Kirby presented the two-step algorithm for evaluating lesions with a dermatoscope. The first step is to determine if a lesion is melanocytic or nonmelanocytic. To determine if a lesion is melanocytic, a known pigment pattern needs to be identified, such as reticular or globular patterns. In addition, it is important to determine the homogeneity of these lesions. If a lesion is determined to be melanocytic, the second step is determining whether the lesion is benign, suspect, or malignant.
Reassuring dermoscopic features of lesions were highlighted by Dr. Kirby and include coral-like or gyri/sulci as seen in seborrheic keratoses and the lacunae and septae of angiomas. Dr. Kirby also reviewed specific features that are concerning for melanoma such as atypical pigment network, radial streaks, shiny white structures, negative network, peripheral light brown structureless areas, and atypical vasculature.
Furthermore, Dr. Kirby illustrated the dermoscopic evaluation of acral lesions. She reviewed the “Ridges are Risky” and “Furrows are Friendly” approach to these lesions to determine if features are concerning for melanoma. Next, she reviewed specific findings that are concerning for amelanotic melanomas such as glomeruloid coils, polymorphous vessels, and structureless pink “blobs” with white shiny structures. Finally, Dr. Kirby reviewed specific features of common benign lesions, polarized vs nonpolarized light, and the different types of dermatoscopes.