Lentigo Maligna Melanoma

Lentigo maligna melanoma is a type of melanoma of the skin. It’s most frequently found in areas of the body that have been exposed over time to too much ultraviolet (UV) light from the sun, such as the face, head, neck or arms. It’s relatively slow-growing, sometimes developing over the course of years and not being diagnosed until later adulthood.

Lentigo Maligna vs. Lentigo Maligna Melanoma

Lentigo maligna is the term used to describe a precancerous stage of lentigo maligna melanoma. It may sometimes also be referred to as an “in situ” form of lentigo maligna melanoma.

Lentigo maligna develops in skin that has been damaged over time by the sun’s UV light. This can cause a brown or black spot or lesion that is not yet cancerous, but that contains precancerous cells. If these cancer cells start to spread further into the surrounding tissue, then lentigo maligna develops into its cancerous form, lentigo maligna melanoma. Studies have shown that up to 50% of lentigo maligna cases may turn into lentigo maligna melanoma.

The most significant risk factors for lentigo maligna melanoma, which are things that make it more likely someone will develop the condition, are:

• Being an older adult, in particular over the age of 60
• Having been exposed to more-than-average amounts of UV light over time

Other possible risk factors include having:

• A family member who has been diagnosed with a form of melanoma
• A prior diagnosis of another form of skin cancer
• A history of long-term use of tanning beds
• Fairer or lighter-colored skin

Cancer doctors may use a range of tests to accurately diagnose lentigo maligna melanoma.

• Lentigo maligna melanoma dermoscopy is a procedure during which a doctor uses a dermoscope – which is a magnifying tool similar to a microscope – to examine any moles or lesions that may contain cancer.
• A physical examination and discussion of a patient’s medical history can help determine whether they have signs of lentigo maligna melanoma or are at higher risk of developing the condition.
• Excision is the process of removing the whole of a suspected lentigo maligna melanoma lesion under general anesthetic. After removing the lesion, it may be examined in a lab for signs of cancer.
• An incisional biopsy is the removal of a small sample of a lesion for examination in a lab to help determine whether someone has lentigo maligna melanoma.

After diagnosis, a doctor may stage the cancer using a staging system similar to the one used for other forms of melanoma.

Learn more about the melanoma stages

For patients diagnosed with lentigo maligna melanoma, choosing the best treatment options depends on a variety of factors, including where the cancer is, whether it has spread from its original location and a patient’s age and health. Many patients benefit from one or more options, including:

• Surgery to remove the lesion that is suspected to be cancerous, as well as a small amount of surrounding tissue (referred to as a margin)
• Radiation therapy, which uses high powered radiation to destroy cancer cells
• Immunotherapy options, which boost the body’s natural immune system so that it can more effectively fight off cancer

People who are diagnosed with lentigo maligna melanoma are cared for by experts on a multidisciplinary team. This may include:

• Dermatologists who specialize in disease of the skin health
• Mohs surgeons, who are specially-trained surgeons who act as the pathologist and surgeon and can provide real-time analysis of the margins
• Surgical oncologists with expertise in conventional and advanced surgical techniques for removing melanomas
• Medical oncologists, who are experts in using medications like immunotherapy
• Radiation oncologists with training in the latest radiation therapy procedures
• Trained oncology nurses, who specialize in working with cancer patients throughout their cancer journey
• Supportive care specialists, who provide physical, mental and social support during and after treatment

One study found that after successfully removing all of the cancer, 87% of lentigo maligna melanoma patients survived at least three years, while 74% survived longer than 10 years. It’s important to speak with the care team to get a personalized lentigo maligna melanoma prognosis based on the patient’s cancer subtype, stage and overall health.