What is lentigo maligna melanoma?

Updated: Mar 08, 2019
  • Author: Jonathan B Heistein, MD; Chief Editor: Gregory Gary Caputy, MD, PhD, FICS  more...
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Answer

Lentigo maligna melanomas represent 4-10% of melanomas. On a cellular level, dermal and epidermal changes from sun exposure must be present. The histologic appearance is one of irregularly shaped hyperchromatic cells that form spindle-shaped nests. The epidermis is atrophic, while the dermis contains solar elastosis with chronic inflammatory infiltrates. From a clinical standpoint, lentigo maligna melanomas are often larger than 3 cm, flat, tan, and begin as small, frecklelike lesions (see image below). They occur in sun-exposed areas (eg, face and neck of older individuals). Marked notching of the borders is present. Lentigo maligna melanoma usually arises within a Hutchinson freckle (lentigo maligna). When tumor thickness and location are taken into consideration, the prognosis for these melanomas is not believed to be worse than that for other subtypes. [13]

Lentigo maligna melanoma, right lower cheek. Centr Lentigo maligna melanoma, right lower cheek. Centrally located erythematous papule represents invasive melanoma with surrounding macular lentigo maligna (melanoma in situ). Courtesy of Susan Swetter, MD.

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