What is a common premalignant lesion caused by sun exposure that can develop into squamous cell carcinoma?

Actinic keratosis is a common premalignant lesion that arises as a result of prolonged sun exposure. It typically presents as rough, scaly patches on sun-damaged skin, notably on areas such as the face, ears, neck, scalp, and the backs of the hands. Over time, these lesions have the potential to progress to squamous cell carcinoma, especially in immunocompromised individuals or in those with a history of extensive sun exposure.

The process involves the accumulation of genetic damage in the skin cells due to ultraviolet (UV) radiation, leading to abnormal keratinocyte proliferation. While actinic keratosis can appear benign, the risk for malignant transformation underscores the importance of monitoring and treating these lesions. Treatment options often include topical therapies like 5-fluorouracil, cryotherapy, or laser therapy, aimed at preventing progression to squamous cell carcinoma.

Other choices such as basal cell carcinoma and seborrheic keratosis do not share the same level of premalignancy associated with actinic keratosis. Basal cell carcinoma is typically not considered a precancerous condition as it is a form of skin cancer in its own right. Seborrheic keratosis, while it may appear