What are the other Names for this Condition? (Also known as/Synonyms)

• Hutchinson’s Melanotic Freckle
• Lentigo-Melanosis
• Melanosis Circumscripta Precancerosa

What is Lentigo Maligna? (Definition/Background Information)

• Normal skin is composed of 3 layers - the epidermis, the dermis, and the subcutis. The epidermis and dermis are separated by a layer, called the basement membrane
• A melanoma is a type of cancer that develops from cells, called melanocytes. Melanocytes are cells that produce melanin; the pigment that gives skin its color
• Melanomas that are confined to the epidermis and have not yet penetrated through the basement membrane are called melanoma in situ of skin
• Lentigo Maligna (LM) is a type of melanoma in situ of skin that is generally seen as a solitary pigmented lesion on the head and neck region (mostly on the face). It generally occurs in older adults following severe sun-exposure and skin damage
• In a vast majority of cases, severe and long-term exposure to sunlight precedes the development of these lesions. Sometimes, a large area of the skin may be involved and an irregularly pigmented patch seen
• Lentigo Maligna is diagnosed with a confirmatory biopsy. Once a definitive diagnosis is made, it is surgically removed (excised). The prognosis for such cancer types, which have been diagnosed early and excised completely, is typically excellent

Who gets Lentigo Maligna? (Age and Sex Distribution)

• Lentigo Maligna can occur in young as well as old individuals; however, most of the cases are observed between the age range of 40-80 years (average age of 65 years)
• Both male and female genders are affected, though a male predominance is observed
• In general, melanomas of skin occur more frequently in Caucasians, as compared to other races

What are the Risk Factors for Lentigo Maligna? (Predisposing Factors)

The following factors increase the risk for Lentigo Maligna:

• Exposure to the ultraviolet (UV) rays of sun is a major risk factor. UV rays are present in sunlight, and also in tanning lamps and beds. A severe exposure to sunlight is a major risk factor for Lentigo Maligna; the severe exposure mostly occurs due to the nature of one’s work/occupation
• Nevus (medical term for mole) is a non-cancerous pigmented tumor. While most nevi never become cancerous (or malignant), a small number of atypical/dysplastic nevi (moles with abnormal shape/borders/color) may turn cancerous. When such dysplastic nevi run in families, the condition is called dysplastic nevus syndrome. Individuals with this condition have a 10% increased risk of developing melanoma. Despite the above and irrespective of the condition, whether the nevi are present since birth, or are normal, or atypical; more the number of moles, more is the risk
• The presence of actinic keratosis; a precancerous condition caused by sun exposure
• Fair-skinned individuals are at a higher risk; more so those with freckles or those who develop sunburns easily
• Previous history of melanoma or a history of melanoma in parents/siblings
• An inherited condition called xeroderma pigmentosum, where the ability of the cells to repair sun-induced damage to genetic material is impaired
• Weakened immune system, as a result of infections (such as HIV), drugs (chemotherapy or immunosuppressants), and the presence of cancers (such as lymphoma)

Note: Lentigo Maligna usually affects the face (head and neck area). When compared to melanomas affecting other body regions (apart from the head and neck area), individuals with LM are not known to have more than 60 nevi/moles.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Lentigo Maligna? (Etiology)

Lentigo Maligna is associated with severe sun-exposure and develops from the melanocytes in the skin. A long-term (accumulated) exposure to sunlight that results in DNA damage, is generally observed with this skin condition.

• UV-radiation induces damage to DNA (genetic material that determines all of our traits and functions), which in turn may turn-on oncogenes, or turn-off tumor suppressor genes
• Uncontrolled activity of oncogenes (rogue genes that promote cell growth and division) or depressed action of tumor suppressor genes (genes that normally keep a check on cell growth and division) is thought to play a role in the development of melanomas
• In rare cases, an association of Lentigo Maligna with BRAF gene mutation has been noted. Also, chromosomal losses on chromosomes 13 and 10 have been reported
• In families with inherited melanomas, gene mutations that increase the risk of cancer are passed on from one generation to the next

What are the Signs and Symptoms of Lentigo Maligna?

Lentigo Maligna signs and symptoms may include the following:

• Presence of a pigmented skin lesion on the sun-exposed area of the body; in most cases, the face (or head and neck region) is involved
• In the face, the skin lesions have also been described as Hutchinson’s Melanotic Freckles
• The skin lesion is usually small-sized, slow-growing, around or greater than 6-10 mm in size, and of non-uniform discoloration (usually light brown or black)
• They may be present as macules; a macule indicates the presence of a flat, distinct, discolored area of skin that usually does not involve any change in the thickness or texture of the affected skin
• In some cases, larger areas may show irregularly-shaped but flat, light or dark (variable) pigmented, skin patches
• In case of larger skin lesions or patches, there may be the presence of nodules within the irregular patch formation
• The skin pigment (in such large patches) may take on varying dark to light shades. Due to this, it sometimes becomes difficult to differentiate between the boundaries of discolored patterns and normal skin; i.e., the edges of the lesions may be skin-colored (called amelanotic Lentigo Maligna)
• The larger the size of presumed Lentigo Maligna (LM), the greater is the chance of invasion somewhere within the lesion. With invasion, the diagnosis will change to Lentigo Maligna Melanoma  (LMM), with a worse prognosis. In general, if LM lesions are over 4 cm in size, then there is a 50% chance of invasion into the deeper skin layers being found on a thorough pathologic examination of the full specimen
• A suspicious pigmented area/spot showing a spread of color to the surrounding skin and with swelling, redness, or itching (due to inflammation). Such areas may also be scaly, or exhibit some oozing of fluid, or bleeding

How is Lentigo Maligna Diagnosed?

A thorough history and a complete physical exam by a physician are crucial for the diagnosis of Lentigo Maligna. Sun exposure for a long duration is usually noted by the healthcare provider.

This is followed by some tests which include:

• Biopsy of skin: A sample of the skin, from any suspected area found on physical examination, is taken and examined under a microscope for signs of cancer by a pathologist. The types of biopsy performed include:
  • Excisional biopsy: After numbing the area with a local anesthetic, the entire mole is removed with a small border of surrounding skin. Where possible, this is the generally preferred method
  • Punch biopsy: After numbing the area with a local anesthetic, a circular blade is pressed into the skin around the suspicious area, and a round piece of skin removed. This type of biopsy is carried out, when the lesion (the suspicious area) is large in size
  • Incisional biopsy: After numbing the area with a local anesthetic, a portion of the tumor is removed using a surgical knife
• Some physicians perform additional screening, such as chest X-ray or blood test, to check for any possible spread
• A differential diagnosis may be necessary prior to establishing a definitive diagnosis, by excluding Paget’s disease of skin and squamous cell carcinoma in situ (mostly when amelanotic Lentigo Maligna is observed)

Note:

It is very important to distinguish between Lentigo Maligna and Lentigo Maligna Melanoma. Lentigo Maligna can resemble the following (mostly benign) conditions clinically:

• Common mole
• Freckle
• Seborrheic keratosis
• Pigmented actinic keratosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Lentigo Maligna?

The complications of Lentigo Maligna may include:

• The complications of Lentigo Maligna may include:
• The skin lesions or surgical outcome on the face may present cosmetic issues
• Recurrence following surgical removal of the skin lesions is not uncommon
• In some cases, the necessity for multiple surgeries to completely treat the condition

How is Lentigo Maligna Treated?

Lentigo Maligna may be treated as follows:

• When a diagnosis of melanoma in situ is made after a biopsy, a re-excision of the original site is done along with some surrounding area of normal, non-cancerous skin (called a margin)
• The extent of the margin is determined by a surgeon after considering a number of factors while although commonly, a margin of 0.5 centimeters in every direction around the original cancer, is accepted as standard
• This excision is performed under a local anesthetic in most cases
• Mohs-assisted micrographic surgery is frequently performed for Lentigo Maligna. This technique uses special immunohistochemical stains to  detect the differences between benign and malignant pigment cells
• After a complete removal of the Lentigo Maligna, closure of the defect is necessary. This is done by second intention healing, a skin graft, or flap surgery. The choice is made based on what will lead to the best functional and cosmetic result

Note: Since it can be very difficult to clinically distinguish between normal/healthy skin and the irregular melanoma patches that show little to no pigmentation, a complete surgical excision and removal of the skin lesion may be difficult and may not be achieved. Due to this, the chances of local recurrence at the site of surgery remains high. Thus, more than one surgical procedure may be required until the tumor is completely removed.

How can Lentigo Maligna be Prevented?

A few steps towards preventing Lentigo Maligna may include:

• Avoid direct exposure to UV rays and remain in the shade, as and when possible
• When heading out into the sun:
  • Slip on a shirt
  • Slop on some sunscreen. Sunscreens with SPF values higher than 30, and those offering broad spectrum protections (against UV-A and UV-B rays), are recommended. Apply an ounce to all exposed areas, 30 minutes before heading outdoors. Reapply every two hours, and also after excessive sweating
  • Slap on a hat
  • Wrap on sunglasses

This is encapsulated as the “Slip! Slop! Slap! Wrap” method for skin cancer prevention. (Source: The American Cancer Society, Atlanta)

• Avoid tanning beds and sun lamps
• Perform self-examination of your skin, from head to toe, once a month
• Get a professional skin exam from a healthcare provider, once a year
• All patients with melanoma should undergo skin examinations regularly even after treatment, at least once a year throughout their lives

What is the Prognosis of Lentigo Maligna? (Outcomes/Resolutions)

• A majority of individuals with Lentigo Maligna have an excellent prognosis following complete excision of the tumor
• It has been noted that almost all those who are diagnosed with stage-0 melanoma in situ, survive for 5-10 years after diagnosis. The overall 5- or 10-year survival rates are nearly 99-100%

Nevertheless, the prognosis depends upon a set of several factors, which include:

• Stage of tumor: With lower-stage tumors, when the melanoma is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage cancers, such as those with metastasis, the prognosis is poor
• Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
• Age of the individual: Older individuals generally have poorer prognosis than younger individuals
• The size of the melanoma: Individuals with small-sized melanomas fare better than those with large-sized ones
• Thickness of the tumor
• Individuals with bulky disease have a poorer prognosis
• Involvement of vital organs may complicate the condition
• The surgical resectability of Lentigo Maligna (meaning if it can be removed completely)
• Whether the cancer is occurring for the first time, or is recurrent. Recurring cancers have worse prognosis compared to those that do not recur
• Response to treatment: Melanomas that respond well to treatment have better prognosis compared to melanomas that do not respond to treatment
• Progression of the condition makes the outcome worse

An early diagnosis and prompt treatment of the condition generally yields better outcomes than a late diagnosis and delayed treatment.

Additional and Relevant Useful Information for Lentigo Maligna:

• According to the American Joint Committee on Cancer TNM system, melanoma in situ is categorized as stage 0 (Tis N0 M0), meaning that the tumor is confined to the epidermis and there is no involvement of the lymph nodes or other distant organs.
• Melanoma is the most common form of cancer in young adults, aged 25-29 years. 1 in 50 Americans have a lifetime risk of developing melanoma
• The ‘Slip-Slop-Slap campaign’ was initially launched in Australia by Cancer Council Victoria in the 1980s, to promote awareness about skin cancer and methods for its prevention. This was then adopted in New Zealand as the ‘Slip-Slop-Slap-Wrap campaign’ (Source: The Wikipedia)