Assessing the Dermal Epidermal Junction of Hyperkeratotic Actinic Keratoses via Line-Field Confocal Optical Coherence Tomography

Introduction: Actinic keratoses (AKs) are ultraviolet (UV)-induced skin lesions that may progress to invasive squamous cell carcinoma. Hyperkeratotic AKs hinder line-field confocal optical coherence tomography (LC-OCT) imaging, limiting assessment of the dermal-epidermal junction (DEJ) and PRO-score, a histopathological index of dermal invasion. Objective: The aim of this study was to evaluate whether moisturization improves DEJ visualization and PRO-score evaluation in hyperkeratotic AKs using LC-OCT. Materials and methods: Fifty-nine hyperkeratotic AKs were randomized to receive either 20-min tap water occlusion or 20% salicylic acid ointment (SAO). LC-OCT scans were taken before and after treatment. DEJ visibility, PRO-score (0-3), and confidence in PRO assignment (cPRO) were rated by blinded evaluators. Results: DEJ visibility significantly increased posttreatment (from 39.0% to 86.4%, p = 0.015), with no significant difference between water and salicylic acid ointment (SAO). Confidence in PRO-scoring also improved (p < 0.001), and 39.1% of lesions with initial scores were reclassified. G2 AKs had higher DEJ visibility than G3 both before and after treatment. Conclusion: Moisturization enhances LC-OCT evaluation of hyperkeratotic AKs, improving DEJ visualization and diagnostic confidence.