Validation of Dermoscopy as a Real-time Noninvasive Diagnostic Imaging Technique for Actinic Keratosis

OBJECTIVE: To validate dermoscopy as a real-time noninvasive diagnostic imaging technique for actinic keratosis (AK). DESIGN: Prospective study to validate a diagnostic test. SETTING: Dermatology department of a tertiary university hospital in Fuenlabrada, Madrid, Spain. PATIENTS: A total of 178 patients with a clinical diagnosis of AK participated in the study. MAIN OUTCOME MEASURES: An independent blinded comparison was performed between dermoscopy results and histopathological findings, the gold standard for the diagnosis of AK. All the patients underwent both diagnostic tests. RESULTS: One hundred seventy-eight lesions were evaluated. The concordance between dermoscopy results and histopathological findings was 0.917. The sensitivity of dermoscopy for the diagnosis of AK was 98.7%, with a specificity of 95.0%, a positive likelihood ratio of 19.74, and a negative likelihood ratio of 0.01. A diagnostic algorithm that combined follicular openings and erythematous pseudonetwork demonstrated a sensitivity of 95.6% and a specificity of 95.0% for the diagnosis of AK. CONCLUSIONS: The sensitivity and specificity of dermoscopy for the diagnosis of AK were high, as was the concordance between dermoscopy results and histopathological findings. As a real-time noninvasive diagnostic imaging technique for AK, dermoscopy may be incorporated in the management of patients with these lesions.