Melanoma in situ/Lentigo maligna: Wo und bei wem sollte ich darauf achten?

Introduction: Lentigo maligna (LM) is a rare form of in situ melanoma, frequently seen as a large patch in elderly patients. The aim of this study was to assess clinical and dermoscopic features of LM. Material and Methods: A retrospective study of LM patients presenting to our center between July 2007 and July 2017 was performed. Demographic data, anatomical location, laterality, diameter, Clark level, Breslow stage, ‘ABCD' signs and dermoscopic features were registered. Facial versus extrafacial LM were compared. Results: We found 21 LM, of which 12 had an extrafacial location and 9 a facial location. Half of the extrafacial lesions were located on an upper limb. The median age at diagnosis was 63 years (ranging from 38 to 84 years). Most LM cases were female (16/21) with phototype II (13/21). More than half of the patients (11/21) had a history of a skin neoplasm or actinic keratosis. The median diameter found was 6 mm (interquartile range = 4.5 mm), ranging from 1 to 15 mm. Five lesions were invasive (median Breslow depth of 0.2 mm), and 4 of them were extrafacial. Discussion: In this study LM was more frequently found in an extrafacial location and as a small patch with a 6-mm diameter medium. The epidemiology of LM/LM melanoma might be changing. Full body examination and dermoscopy are of the utmost importance for the diagnosis. Dermatologists should be aware and search for small lesions outside the face and neck, particularly in middle-aged female patients with photo-damaged skin.