Though the vast majority of actinic keratoses remain benign, they reveal that you have sustained sun damage and could develop any kind of skin cancer, especially the second most common form of the disease, squamous cell carcinoma (SCC).
If you have one AK, you may develop others. The more AKs that remain untreated, and the older these lesions are, the greater the chance that one or more may become an SCC. In fact, some scientists interpret AK as the earliest form of SCC. (In rarer instances, AKs may also turn into basal cell carcinoma, the most common form of skin cancer.)
An untreated SCC can become invasive and even life-threatening. Actinic cheilitis, a variant of actinic keratosis, is an often aggressive type of precancer on the lower lips that is at heightened risk of turning into an invasive SCC. Once a cancer arising from actinic cheilitis penetrates the outer layer of the lip (mucosa, mucous membranes ) skin, it may bleed, develop a sore that doesn’t heal, become infected and even spread to internal organs.
Though at most about 10 percent of AKs turn into cancers, the majority of SCCs begin as AKs, and there is no way to know ahead of time which ones are precursors of squamous cell carcinoma. Fortunately, we have many effective treatments for eliminating AKs.
Actinic cheilitis: lower lip with protruding sore, white patches and cracks with dried blood, a possible mix of actinic cheilitis and skin cancers.
Mark Lebwohl, MD
Deborah S. Sarnoff, MD