Premalignant Lesions

Premalignant lesions that are common in the elderly include actinic keratoses, Bowen's disease, and lentigo maligna.

Actinic Keratoses

Premalignant lesions occurring in sun-exposed areas that may give rise to squamous cell carcinomas.

Actinic keratoses are the most common type of premalignant skin lesion. They are caused by ultraviolet light, which induces mutations. Risk factors include older age, fair complexion, blue eyes, and a history of childhood freckling.

Symptoms and Signs

The lesions are scaly sandpaper-like patches, varying in color from skin-colored to reddish-brown or yellowish-black, that occur on sun-exposed areas. Lesions may be single or multiple. They are usually painless but may be slightly tender.

Prognosis and Treatment

A lesion may evolve into a squamous cell carcinoma, but the latent period is long, and the squamous cell carcinoma usually grows very slowly and rarely metastasizes. Patients with actinic keratoses are at high risk of developing other forms of skin cancer as well.

Avoidance of sun exposure leads to regression of early actinic keratoses and may be sufficient therapy for patients with mild disease. Patients with multiple skin lesions should be screened every 6 to 12 months for skin cancer. Patients should be advised to use a broad-spectrum sunscreen with a sun protection factor (SPF) > 15. For only a few lesions, cryotherapy with liquid nitrogen or curettage and light cautery may be used. Particularly for multiple lesions, topical 5-fluorouracil (5-FU) can be used. For facial lesions, a 1 or 2% solution or 1% cream can be used. For lesions on the trunk or limbs, 5% 5-FU cream can be applied. Cream or solution should be applied once or twice a day. Treatment with 5-FU produces progressive erythema and burning and, after 2 to 4 weeks, ulceration followed by reepithelialization over another 2 weeks. Treatment should be discontinued once ulceration occurs. Complete healing usually occurs within 2 months, and the patient has far fewer lesions for months to years thereafter. Pain and burning sensations can be decreased, especially on sensitive areas such as the face, by first applying a 1 to 2% 5-FU solution, then 15 to 20 minutes later applying a medium-potency corticosteroid cream. Patients must be told to avoid the eyes and mucous membranes when applying 5-FU, to follow the directions in the package circular exactly, and to never leave the medication on longer than directed. Tretinoin cream can be combined with 5-FU, especially if lesions appear on more resistant areas such as the trunk or limbs. Masoprocol may be used as an alternative to 5-FU.

Bowen's Disease

(Squamous Cell Carcinoma In Situ)

Premalignant lesions, often due to arsenic exposure, that may give rise to squamous cell carcinomas.

These lesions predominantly affect the elderly. Sun exposure is a probable contributing cause in many patients, although some patients may have a history of arsenic exposure (either medicinal or occupational). Human papillomavirus (HPV) may also play an etiologic role.

Symptoms and Signs

Lesions consist of persistent, erythematous, scaly plaques with well-defined margins. Lesions can occur anywhere on the skin or mucous membranes and may be single or multiple.

Prognosis and Treatment

Multiple lesions are associated with an increased incidence of internal malignancies and mandate close follow-up. Treatment options include excision, cryotherapy with liquid nitrogen for 15 to 20 seconds, curettage and cautery, and topical 5-fluorouracil.

Lentigo Maligna

(Hutchinson's Freckle)

Premalignant lesions that may give rise to lentigo maligna melanoma.

Symptoms and Signs

These lesions are pigmented macules, often > 1 cm in diameter with an irregular border, occurring mainly on sun-exposed areas, particularly the cheeks and forehead. Lesions characteristically have brown, black, red, and white areas and become more irregularly pigmented over time. Gradually, lesions expand in a prolonged radial (superficial) growth phase. Nodule development, with or without bleeding, signifies invasion and conversion to lentigo maligna melanoma.

Prognosis and Treatment

Risk of conversion to melanoma by age 75 is estimated at 1 to 2%.

Patients should undergo regular follow-up examinations for signs of conversion to melanoma. Some authorities suggest cryotherapy or argon laser therapy to decrease the number of abnormal melanocytes and thus, theoretically, to reduce the risk of developing melanoma. However, both of these procedures have a high recurrence rate. Because conversion to melanoma is usually relatively slow, the decision to excise lentigo maligna should be based on several factors, including the size and location of the lesion, which determines the complexity of the procedure required, and the patient's life expectancy and comorbidities.