Background: Actinic keratosis or solar keratosis is a common skin lesion caused by sun damage that progresses to squamous cell carcinoma. It has been suggested that actinic keratosis is in fact SCC in situ. Objective: This literature review was conducted to investigate the differences between actinic keratosis and squamous cell carcinoma and whether actinic keratosis should in fact be managed as squamous cell carcinoma. Methods: A literature review was conducted to assess the differences between actinic keratosis and squamous cell carcinoma. We conducted searches of Pubmed, Cochrane and Medline for articles published between January 1, 2000 and April 30, 2014, using the following search terms: actinic keratosis, solar keratosis, skin cancer, squamous cell carcinoma, dermoscopy, sun exposure, ultra violet radiation, and dysplasia. Studies published in English were selected for inclusion in this review as were additional articles identified from bibliographies. Results: It is difficult to distinguish between both actinic keratosis and squamous cell carcinoma. Perhaps a classification system for actinic keratosis including early in situ SCC type AK1, early in situ SCC type AK2 and in situ SCC type actinic keratosis is needed. Conclusion: Actinic keratosis invades the basement membrane and as such may progress into invasive SCC. Superficially actinic keratoses are not distinguishable from a superficial SCC and as such may go unrecognized or inaccurately diagnosed.
Retinoblastoma protein function and p16INK4a expression in actinic keratosis, squamous cell carcinoma in situ and invasive squamous cell carcinoma of the skin and links between p16INK4a expression and infiltrative behavior
