title: Actinic keratoses and the incidence of occult squamous cell carcinoma: a clinical-histopathologic correlation.
abstract: BACKGROUND
  The ability to clinically diagnose actinic keratoses (AKs) lesions has been taken for granted for some time. The importance of the malignant potential of these lesions is well known. However, a recent Phase IV, multicenter study assessing the long-term benefit of aminolevulinic acid-based photodynamic therapy provided a unique opportunity to prospectively examine the clinical histopathologic correlation of AKs.
  
  
  OBJECTIVE
  The objective was to characterize the histopathology of clinically diagnosed AK lesions in the study population.
  
  
  METHODS
  Punch biopsies of 220 clinically diagnosed untreated AKs were performed at baseline plus 51 lesions unresponsive to treatment (total, 271).
  
  
  RESULTS
  Clinical diagnosis and histopathologic findings agreed in 91% (246/271) of the lesions biopsied. The balance of the biopsied lesions were: (1) benign changes 4% (11/271) and (2) occult cutaneous malignancy in 5% (14/271) of the cases, 12 squamous cell carcinomas and 2 basal cell carcinomas.
  
  
  CONCLUSIONS
  In this study, about 1 in 25 clinically diagnosed AK lesions identified by board-certified dermatologist investigator(s) were occult early-stage squamous cell carcinomas on histologic assessment, a fact surmised by the medical community that until now had not been well quantified. These findings should be considered when clinicians decide how to treat and manage AK patients.
authors.affiliation: Cockerell and Associates Dermatopathology Laboratory, Dallas, Texas, USA.
authors.forename: Torsten
authors.initials: T
authors.lastname: Ehrig
authors.forename: Clay
authors.initials: C
authors.lastname: Cockerell
authors.forename: Daniel
authors.initials: D
authors.lastname: Piacquadio
authors.forename: Syd
authors.initials: S
authors.lastname: Dromgoole
mesh_terms: D001706:Biopsy; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D003937:Diagnosis, Differential; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D007642:Keratosis / Q000473:pathology*; D011230:Precancerous Conditions / Q000473:pathology*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology*