A 79-Year-Old Man with a Pigmented Lesion on the Scalp

Abstract

Lentigo maligna is classified as a type of melanoma in situ. It accounts for 79%–83% of all cases of melanoma in situ. The lifetime risk of progression from lentigo maligna to lentigo maligna melanoma ranges from 5% to 50% and increases with time. The condition most commonly affects patients aged between 65 and 80 years. Men are more commonly affected compared to women. Clinically, lentigo maligna presents as an asymmetric macule, which slowly spreads centrifugally with increasingly irregular borders. The lesion commonly varies in pigmentation, with shades of tan to black. Lentigo maligna affects mainly chronically sun-damaged skin, most commonly on the head and neck. Histopathological examination is the gold standard for diagnosis of lentigo maligna. Dermoscopy may be useful in establishing of initial diagnosis and selection of the biopsy site. Complete surgical removal of lentigo maligna with 5 to 10-mm clinical margins is the preferred management. Topical imiquimod 5% cream as the second-line treatment is recommended when surgery is not possible at the outset (primary setting) or when optimal surgery has been performed (adjuvant setting). Radiotherapy may be also used for nonsurgical candidates.