Lentigo maligna



Lentigo maligna


Darrell S. Rigel, Ellen S. Marmur and John A. Carucci


Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports


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Lentigo maligna (LM) is a type of melanoma in situ that classically presents as irregular pigmented patches on sun-exposed areas of the face and neck in older individuals. If left untreated, the lifetime risk of LM progressing to invasive melanoma (lentigo maligna melanoma, LMM) varies from 4.7% to 2.2%. LM and LMM are the most common forms of melanoma on the head and neck, are commonly found on the cheek, often present as a cosmetic concern, and their incidence is increasing. Treatment has been difficult owing to high recurrence rates, which are attributed to subclinical extension and the difficulty of determining tumor margins.


The first treatment of choice for LM is wide local excision with a margin of at least 5 mm, which leads to clearance rates of 24–70% and recurrence rates of 7–20%. Staged surgical excision is associated with recurrence rates of 0% to 9.7%. In some patients, surgical treatment will inevitably lead to large skin defects and complex surgical reconstructions. Combination therapy with both surgical and non-surgical modalities, and surgery with wider margins are at the forefront of research in the field of LM/LMM.



Management strategy


Successful management of LM depends on early diagnosis and definitive removal. The differential diagnosis includes lentigo, macular seborrheic keratosis, pigmented actinic keratosis, pigmented squamous cell carcinoma in situ, and pigmented superficial basal cell carcinoma. Confirmatory biopsy is necessary prior to definitive treatment. The use of a Wood’s lamp may help to determine the perimeter of the lesion. Dermoscopy may also be helpful. Biopsy of the entire lesion is ideal in order to ascertain its maximum depth. However, the lesion tends to be large (>1 cm) owing to its propensity for extensive radial growth prior to vertical growth into the dermis. Therefore, biopsy of part of the lesion is often performed. Treatment is primarily surgical, although eradication by other methods may be considered. Patients with a history of LM should have periodic full-body skin examinations by a dermatologist to allow for early detection of recurrence, progression, or a second primary skin cancer. Patients with LM also require a consultation about sun protection behaviors.




First-line therapies


















image Excision A
image Mohs micrographic surgery D
image Modified Mohs surgery D
image Staged excision D









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Aug 7, 2016 | Posted by in Dermatology | Comments Off on Lentigo maligna

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