Solar lentigines, while common in older adults, can indicate malignancy

Key Points

Sacramento, Calif. - Solar lentigines are common in the aging patient, with 90 percent of Caucasians over age 60 having the condition. Even those who diligently used sunscreen may experience lentigines, because most sunscreens don't block all UV waves.

"Older people are at risk because they've spent more time on the planet, specifically more time in the sun," says Suzanne L. Kilmer, M.D., founding director of Laser and Skin Surgery Center of Northern California, Sacramento, Calif.

Solar lentigines are more prevalent among fair-skinned patients. Although dark-skinned individuals also can have lentigines, the higher melanin content in their skin provides some photoprotection.

"This is where I think people get into trouble," Dr. Kilmer says. "The biggest issue is to accurately diagnose these in the first place."

Looking for differences

Some clinicians might not be too concerned about these cosmetic defects because they are normally benign. The index of suspicion would increase if the lentigo looks different from the others around it, especially if it is a different color, changes shape, or is bleeding. If it looks symmetrical, evenly pigmented and like the others, it is most likely benign.

However, many dermatologists are looking at patients for the first time and they might not recognize that the lentigo is changing. Under these circumstances, Dr. Kilmer says she would have a higher index of suspicion if the patient is concerned, because the physician might miss a subtle change in the lesion. Listen to the patient, she says.

If the patient refuses a biopsy, clinicians should take a photograph of the lesion and schedule a follow-up. At the follow-up, the physician can compare the lentigo with the photograph and prove it is changing.

Even if they look normal, a dermatologist should provide periodic follow-up for anyone with many lentigines because they are a sign that the person has the No. 1 risk factor for developing skin cancer - a lot of sun exposure.

Solar lentigines are small, uniformly pigmented macules that are formed from hyperplasia of keratinocytes and melanocytes. There is a build-up of melanin in the keratinocytes, Dr. Kilmer says. The surrounding skin appears normal. The pigmented lesions are induced by exposure to ultraviolet (UV) light and can appear as solitary or multiple lesions.