actinic keratosis

Last edited 02/2022 and last reviewed 02/2023

  • Most common premalignant skin condition.
  • Dysplastic proliferations of keratinocytes with a potential for malignant transformation (1).
  • Characterized by multifocal scaly, hyperpigmented or scaly lesions, usually brown with a scaly base.
  • Histologically they are characterised by marked thickening of the keratin layer (hyperkeratosis) and the prickle cell layer (acanthosis). There may be a variable degree of dysplastic change and abnormal mitotic activity. However the basal layer remains intact.

Note 1 - there is debate whether actinic keratoses are premalignant conditions or alternatively early-stage squamous cell carcinoma (SCC). In a study of 459 patients with cutaneous SCC, there were associated adjacent actinic keratoses in 97% of the cases of cutaneous SCC (2).

Note 2 - there has been tremendous variation in the reported risk of progression of actinic keratosis to invasive SCC (between 0.025% to 16% per year). There is currently no existing technology to distinguish between actinic keratosis lesions that will clear, remain stable, or progress to invasive disease. (3)

Click here for example images of this condition

Reference:

Related pages:

clinical features

epidemiology

differential diagnosis

management