Lentigo maligna melanoma is a subtype of melanoma that develops when a lentigo maligna (a subtype of melanoma in situ) progresses from radial to vertical growth with dermal invasion. It accounts for approximately 4%-15% of all melanomas. Fewer than 10% of lentigo maligna cases progress to invasive melanoma, typically over 5-20 years, most often on sun-damaged skin (usually on the face) in individuals aged 60 and older, particularly those with skin phototype I or II.

Lentigo maligna is a slow-growing, irregularly pigmented macule or patch with asymmetry and poorly defined borders. The color may range from tan to dark brown, and lesions may develop palpable plaques or nodules that signal dermal invasion. Lesions may ulcerate or bleed. The average growth rate has been reported as approximately 0.13 mm per month.

Lentigo maligna melanoma is associated with chronic sun damage and may occur in patients with a history of nonmelanoma skin cancers. Additional associations include immunosuppression, Werner syndrome, oculocutaneous albinism, xeroderma pigmentosum, and germline mutations in melanoma predisposition genes, including CDKN2A, CDK4, MC1R, BAP1, TERT, POT1, MITF, TP53, PTEN, CHEK2, and BRCA1 / BRCA2.