Lentigo Maligna Melanoma

Excerpt

Lentigo maligna (LM) is a subtype of melanoma. It commonly presents as an irregular brown macule on chronically sun-damaged skin, particularly the head and neck, in the elderly (see Image. Asymmetric Parallel Ridge Dermoscopic Pattern Indicative of Acral Lentiginous Melanoma on the Heel of a 62-Year-Old Male). It was first described by Hutchinson in 1890 and referred to as “Hutchinson’s melanotic freckle.” For much of the early 20th century, LM was thought to be either benign, infectious, or precancerous due to its slow growth, with names given such as “junctional nevus,” “infective senile freckles,” and “circumscribed precancerous melanosis.” It was not until the late 1970s-80s, spearheaded by research by Silvers, Ackerman, and colleagues that LM became widely recognized as malignant. Today, LM is defined as melanoma in situ (MIS) on chronically sun-damaged skin. Therefore, by definition, LM is confined to the epidermis. The lesion is termed lentigo maligna melanoma (LMM) if it becomes invasive. See Image. Malignant Melanoma. Herein, we review the key aspects of LM/LMM and discuss this disease's unique diagnostic and treatment challenges.