Lentigo maligna (historically also known as a Hutchinson melanotic freckle) is the most common subtype of melanoma in situ, accounting for about 80% of cases. Found most commonly on chronically ultraviolet (UV) radiation-exposed areas of the head and neck in older, phototype I-II individuals, this slow-growing, noninvasive precursor lesion of melanoma is composed of atypical intraepidermal melanocytes. While some distinguish between lentigo maligna and melanoma in situ, lentigo maligna type (the latter of which is thought to be more malignant), the World Health Organization (WHO) recognizes lentigo maligna and melanoma in situ as the same entity.

The natural history of lentigo maligna is that of gradual, asymmetric, radial growth. The majority of lesions are > 6 mm, macular, and variably pigmented with ill-defined, irregular borders. Lentigo maligna has a particular predilection for the nose and cheeks.

Approximately 5% are thought to progress to lentigo maligna melanoma, although it may be several years before this vertical growth phase occurs.

Lentigo maligna and lentigo maligna melanoma have been associated with nonmelanoma skin cancers, Werner syndrome, oculocutaneous albinism, and xeroderma pigmentosa.