Premalignant Epidermal Lesions: Actinic Keratosis

Actinic keratosis is the most common precancerous skin lesion. It usually affects fair-skinned, elderly persons with a history of chronic sun exposure (Fig 10-44). These lesions are typically round, scaly, keratotic plaques that on palpation have the texture of sandpaper. They often develop on the face, head, neck, forearms, and dorsal hands. These lesions are in a state of continual flux, increasing in size and darkening in response to sunlight and remitting with reduced sun exposure. It has been reported that up to 25% of individual actinic keratoses spontaneously resolve over a 12-month period, although new lesions tend to develop continually. The risk of malignant transformation of an individual actinic keratosis is only 0.24% per year, but over extended follow-up, a person with multiple actinic keratoses has a 12%–20% risk of developing squamous cell carcinoma. Squamous cell carcinomas arising from actinic keratoses are thought to be less aggressive than those developing de novo. For lesions arising in the periocular region, incisional or excisional biopsy is recommended. Widespread lesions may be treated with topical 5-fluorouracil or imiquimod cream, cryotherapy, or photodynamic field therapy.

Figure 10-43 Oculodermal melanocytosis.

(Courtesy of Jill Foster, MD.)

Figure 10-44 Multiple actinic keratoses (arrows) near the right eyebrow.

(Courtesy of Cat N. Burkat, MD.)

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.