Ultraviolet radiation (UVR) is the greatest risk factor for FC of the skin. UVR causes FC by inducing key genetic mutations that alter appropriate epidermal cell recycling and apoptotic regulators. Mutations in these markers, especially TP53 and NOTCH, allow for the progression from AK to invasive cutaneous cancers (eg, SCC).
Present data, although limited, suggests both a steady increase in AK prevalence and keratinocyte carcinoma incidence in the United States. At-risk populations include persons of increasing age, chronic UVR exposure, light skin, male sex, and immunosuppression (eg, solid organ transplant recipients, patients with chronic lymphocytic leukemia).
C44.92 – Squamous cell carcinoma of skin, unspecified
D04.9 – Carcinoma in situ of skin, unspecified
L57.0 – Actinic keratosis
189565007 – Squamous cell carcinoma in situ
201101007 – Actinic keratosis
402815007 – Squamous cell carcinoma
Differential Diagnosis & Pitfalls
- Chronic radiation dermatitis
- Inherited syndromes that lead to squamous malignancies including Rothmund-Thomson syndrome and xeroderma pigmentosum. Onset is typically earlier in life.