Premalignant Melanocytic Lesions: Lentigo Maligna
Also known as Hutchinson melanotic freckle or precancerous melanosis or lentigo maligna melanoma in situ, lentigo maligna is a flat, irregularly shaped, unevenly pigmented, slowly enlarging lesion that typically occurs on the malar regions in older white persons. Risk factors for development of lentigo maligna include advanced age, lighter skin types, tendency to develop solar lentigines, and a history of nonmelanoma skin malignancies. A history of intermittent severe sunburns, rather than cumulative sun exposure, is also considered a risk factor for lentigo maligna. Unlike senile or solar lentigo, lentigo maligna is characterized by significant pigmentary variation, irregular borders, and progressive enlargement. These characteristics reflect a radial, intraepidermal, uncontrolled growth phase of melanocytes, which can eventually progress to nodules of vertically invasive melanoma. The absolute risk of a lentigo maligna melanoma (at any location) after a histologically confirmed lentigo maligna is low, at 2.0%–2.6%.
The area of histologic abnormality frequently extends beyond the visible pigmented borders of the lesion; in the periocular region, cutaneous lentigo maligna of the eyelid may extend onto the conjunctival surface, where the lesion appears identical to primary acquired melanosis. Excision with adequate surgical margins is recommended, with permanent sections for final monitoring. Close observation for recurrence is warranted.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.