Actinic keratosis, Bowen disease, and invasive squamous cell carcinoma represent different steps within the disease continuum of squamous neoplasia. Although these stages of squamous neoplasia share common findings, reflectance confocal microscopy may be applied for their differentiation and distinction from other benign or malignant lesions. Hyperkeratosis represents the most important limitation in the evaluation of squamous neoplasia as it may impair the analysis of deeper epidermal and dermal structures significantly.
