It is a brown patch, generally on the face of the elderly. This precursor lesion leads to lentigo maligna melanoma. Clinically it is a spreading brown patch, often with considerable variation in color. It is absolutely flat. It can slowly expand for decades. Over time, a nodule can develop within it, lentigo maligna melanoma.
Lentigo maligna melanoma is the least common type and the slowest growing. It generally has a long radial spread time often reaching large diameters of 3-6 cm or greater and confined to the upper skin layer (epidermis). This is the first stage called lentigo maligna and can last for years. During this stage the melanoma remains in situ. For this reason metastasis is rare. The second stage is called lentigo maligna melanoma and begins when the existing lentigo maligna enters a vertical growth phase.
LENTIGO:
Lentigo (pl. Lentigenes) is a common benign condition. It is characterized by areas of melanocyte proliferation, and hyper pigmentation of the epidermal basal cell layer in a linear fashion. Lentigo - a type of freckle that is a small tan, brown, or black spot, which tends to be darker than the usual (ephelis-type) Freckles and which do not fade in the winter. This kind of spot is referred to as lentigo simplex.
SOLAR LENTIGO:
Solar lentigo is the medical term for "liver spots." These brownish, flat, round or oval spots are a result of sun exposure over many years and usually start showing up during 40s. They are not cancerous, but they can be treated for cosmetic reasons.
The risk of lentigo maligna melanoma increases as the number of years of residence in sunnier climate increases, and risk increases with increased hours of exposure to sunlight, increased amount of actinic damage, and a history of non-melanoma skin cancer. Many consider lentigo maligna to be a pre-invasive lesion induced by long-term cumulative ultraviolet injury. Conceptually, the term melanoma is used when atypical melanocytes invade the rich vascular and lymphatic networks of the dermis, thereby establishing metastatic potential. Lentigo maligna is mostly seen in patients 50 to 80 years old and accounts for ten to 15 percent of skin cancer cases.
Differential Diagnosis
* Seborrhic Keratosis
* Pigmented solar keratosis
* Lentigo maligna
* Freckles
TREATMENT
* The doctor may evaluate sites of lentigo maligna, the speed of progression and the general health and fitness of the patient when choosing a treatment.
* Surgery, radiation therapy and chemotherapy may all be used in the treatment of lentigo maligna.
* Surgery rarely cures the disease, and may be used as a last resort after other treatments have failed.
* After the initial diagnosis, the doctor may recommend the patient be examined every three months for two years, and twice a year thereafter.
* The treatment of choice of lentigo maligna is surgical excision if the lesion is small.
* Radiation therapy is frequently the treatment of choice in the elderly with an extensive lesion.
* These lesions should not be treated with liquid nitrogen cryotherapy, as a rule, because the dysplastic melanocytes go down hair follicles and deep recurrence post-cryotherapy is common
