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Lentigo maligna
See also in: Hair and Scalp
Other Resources UpToDate PubMed

Lentigo maligna

See also in: Hair and Scalp
Contributors: Jeffrey M. Cohen MD, William M. Lin MD, Susan Burgin MD, Lowell A. Goldsmith MD, MPH
Other Resources UpToDate PubMed

Synopsis

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.

Codes

ICD10CM:
D03.9 – Melanoma in situ, unspecified

SNOMEDCT:
302836005 – Lentigo maligna

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Last Reviewed:01/02/2019
Last Updated:10/27/2021
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Patient Information for Lentigo maligna
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Contributors: Medical staff writer

Overview

Lentigo maligna is a form of melanoma skin cancer that is also referred to as "melanoma in situ." It has not invaded the second layer of skin. This means that the skin cells have been damaged enough to become cancerous but not to metastasize (ie, invade the bottom layer of skin and spread to other areas of the body).

Lentigo maligna is most commonly found on sun-exposed areas of skin. This is because the sun produces ultraviolet (UV) radiation, which can damage skin cells. When significant damage has been done, skin cells may become cancerous.

If lentigo maligna is not treated, it can develop into invasive melanoma, which can metastasize (spread to other areas of the body).

If your physician suspects that a lesion may be melanoma, he or she will perform a skin biopsy (a simple procedure to surgically remove the lesion) and then examine a sample of the biopsy under a microscope. Examining the skin under a microscope will allow the physician to establish a precise diagnosis.

Who’s At Risk

Although anyone can develop this disease, lentigo maligna occurs most commonly in older, individuals with light skin who have spent a significant amount of time in the sun. It often occurs on the head and neck, because these areas receive much sun exposure over time.

Signs & Symptoms

The lesion starts as a tan spot on the skin and starts growing larger, darkening, and developing irregular edges. There may be different shades of brown coloring within the patch. It can develop quite slowly over months to years.

Self-Care Guidelines

You can protect your skin from further damage by wearing broad-spectrum sunscreen. Schedule periodic (every 4-6 months) full-body skin examinations with a dermatologist so that he or she can monitor for other skin areas that may need treatment. If you notice a new spot on your skin that concerns you, have a doctor check it.

When to Seek Medical Care

If you notice a new spot on your skin that concerns you, have a doctor check it.

Treatments

After a biopsy confirms the diagnosis of lentigo maligna, complete surgical removal is definitely the treatment of choice. If surgical removal is not possible or desired, there are other treatment options that are effective in some cases. They include radiation therapy, laser therapy, topical creams (imiquimod or tazarotene), and injections (interferon-alpha).
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Lentigo maligna
See also in: Hair and Scalp
A medical illustration showing key findings of Lentigo maligna : Brown color, Face
Clinical image of Lentigo maligna - imageId=688416. Click to open in gallery.  caption: 'A close-up of a variegated, brown, thin plaque.'
A close-up of a variegated, brown, thin plaque.
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