Lentigo maligna and lentigo maligna melanoma in patients younger than 50 years old: A multicentric international clinical-dermoscopic study

Background: LM/LMM is usually diagnosed in elderly patients when it is a large lesion. However, it is important to detect it at an earlier stage to minimize the size of the surgical procedure. Objective: To determine the clinical, dermoscopic and confocal features of LM/LMM in patients <50 years old. Method: This study included cases of consecutively excised LM/LMM arising in patients younger than 50 years if clinical and dermoscopic images were available; confocal images were considered when present. Multicenter study involving tertiary referral centers for skin cancer management. Consecutive patients younger than 50 years with a complete set of clinical and dermoscopic images and histopathological diagnosis of LM/LMM. The aim of this study to define clinical and dermoscopic features related to young age group such as size, dermoscopic criteria and when available, confocal features. Results: A total of 85 LM/LMM of the face from 85 patients younger than 50 years were included in the study. A regression model showed a direct association with the size of the lesion (R2 = 0.08, p-value = 0.01) and with the number of dermoscopic criteria at diagnosis (R2 = 0.12, p-value < 0.01). In a multi variable analysis an increasing number of dermoscopic criteria was correlated with increased age of the patients (p-value < 0.01), while the presence of grey color was a predictor of a younger age at diagnosis (p-value = 0.03). RCM revealed the presence of melanoma diagnostic criteria in all cases (pagetoid cells and atypical nesting). Conclusions: LM is not a disease limited to the elderly as previously thought. LM presenting in young adults tends to be smaller and with fewer dermoscopic criteria making its diagnosis challenging. Careful evaluation of facial pigmented lesions prior to cosmetic procedures is mandatory to avoid incorrectly treating early LM as a benign lesion.