Risk of malignant transformation
Rate of progression to SCC is variable, but approximate lifetime risk is 10%.
- Rate of progression is dependent upon several factors
- Presence of multiple vs single actinic keratosis (AK)
- History of other NMSC
- Without history of NMSC: 0.075% per year
- With at least two NMSC: 0.53% per year
- 40% progression in immunosuppressed transplant patients
97% of SCC arise from AK.
Squamous cell carcinoma that develops from an AK is usually very indolent, but can be invasive.