Lentigo maligna is the precursor to a subtype of melanoma called lentigo maligna melanoma, which is a cancerous (malignant) growth of the cells that give our skin cells color. This variety of melanoma starts as a flat, irregularly bordered brown to tan patch on the skin, typically with variegation in color such that it may darken unevenly over the years. Because of this, the gradual darkening may go unnoticed. The cancer cells may divide and spread locally. If these cancer cells start to spread deeply into the lower layers of the skin (dermis or subcuticular fat), a bump or nodular area may be noticed in the original flat lesion. Once the cells have spread deeply, the term lentigo maligna melanoma is used. When solely the top layer of the skin is affected (epidermis), only the term lentigo maligna is employed.
Lentigo maligna is more prevalent in the elderly population who has seen a high level of cumulative sun exposure in their lifetime. Therefore, commonly affected body regions include the face and forearms. Diagnosis may at times be challenging as this lesion could be confused with benign skin findings such as moles, solar lentigines or seborrheic keratoses. Your dermatologist is specially trained to spot subtle differences between these different lesions. He or she may elect to biopsy those skin findings that are suspect.
The usual treatment for a lentigo maligna is local excision with a 5mm margin of normal tissue. A larger margin or Mohs surgery may be performed if the edges are unclear. Sometimes a lesion is located in a difficult area to excise. In this case, other treatments may be considered including radiation, cryosurgery, or imiquimod cream.
If a biopsy reveals a diagnosis of lentigo maligna melanoma, it is treated in a similar fashion to that of malignant melanoma where the aggressiveness of treatment depends on the pathology report and thickness of the lesion.
Back to Index
The medical information provided in this site is for educational purposes only and is the property of the American Osteopathic College of Dermatology. It is not intended nor implied to be a substitute for professional medical advice and shall not create a physician - patient relationship. If you have a specific question or concern about a skin lesion or disease, please consult a dermatologist. Any use, re-creation, dissemination, forwarding or copying of this information is strictly prohibited unless expressed written permission is given by the American Osteopathic College of Dermatology.