Actinic Keratosis—Can Dermoscopy or RCM Differentiate AK (Not Full Thickness Atypia) from Full-Thickness Atypia/Invasive SCC?

Abstract

Purpose of Review: Actinic keratosis (AK) is the most common sun-induced preneoplastic lesion, and together with photo-aging and skin cancer, it places a huge burden on healthcare systems. The clinical distinction between AK and incipient squamous cell carcinoma (SCC) can be difficult, and therefore, clinical diagnosis is not always reliable and certain. Skin biopsies are sometimes mandatory, and physicians must be aware of the importance of accurate diagnosis and management, as other malignant neoplasms (melanoma, basal cell carcinoma) cannot always be reliably distinguished from AK, especially when pigmented and inflamed. Recent Findings: Although histopathology remains the gold standard for differentiation of AK from SCC, some non-invasive optical technologies such as dermoscopy and reflectance confocal microscopy have recently been applied to enhance clinical diagnosis accuracy and to obtain an in vivo characterization of these lesions. Summary: The combination of dermoscopy with reflectance confocal microscopy improves the clinical assessment and diagnosis of equivocal keratinizing tumors, allows the selection of the most suspicious areas for biopsy, and permits non-invasive determination of treatment outcomes.