Dermatoscopy in "Atypical" Locations – Flat Pigmented Lesions on the Face

Overview

From the point of view of dermatoscopic examination, we consider the face, acral parts of the limb, nails and mucous membrane to be "atypical" locations. The anatomical structure of the skin differs in these areas, and therefore the dermatoscopic findings are also different. On the face of elderly patients, we often diferentiate flat seborrheic keratosis (senile lentigo), pigmented actinic keratosis and lentigo maligna. From the point of view of dermatoscopy, this differential diagnosis is one of the most difficult in clinical practice. Currently, the so-called "inverse approach" is recommended, where we look for dermatoscopic criteria typical of seborrheic keratosis or actinic keratosis (scales, white and enlarged follicles, erythema, brown lines in a parallel or reticular arrangement, sharp lesion boundaries and structures common to seborrheic keratosis). In their absence, we consider the manifestation to be risky with respect to lentigo maligna. In unclear cases, we choose biopsy and histopathological examination.

Keywords:

Face – Actinic keratosis – dermatoscopy – seborrheic keratosis – lentigo maligna