AbstractBackgroundThe treatment of keratinocyte cancers (KC) strictly depends on their differentiation and invasiveness. Non‐invasive diagnostic techniques can support the diagnosis in real time, avoiding unnecessary biopsies. This study aimed to preliminarily define main imaging criteria and histological correlations of actinic keratosis (AK), Bowen’s disease (BD) and squamous cell carcinoma (SCC) using the novel device line‐field confocal optical coherence tomography (LC‐OCT).MethodsDermoscopy and LC‐OCT images of 73 histopathologically confirmed lesions (46 AKs, 11 BD and 16 SCCs) were included in the study. Exemplary lesions (10 AKs, 5 BD and 5 SCCs) were additionally investigated with optical coherence tomography and reflectance confocal microscopy.ResultsMost common LC‐OCT findings of KC in the descriptive statistics were hyperkeratosis/parakeratosis, disruption of stratum corneum, broadened epidermis, basal and suprabasal keratinocyte atypia, dilated vessels/neoangiogenesis and elastosis/collagen alterations. In the univariate multinomial logistic regression, a preserved DEJ was less common in SCC compared with AK and BD, BD displayed marked keratinocyte atypia involving all epidermal layers (bowenoid pattern), while SCC showed ulceration, increased epidermal thickness, keratin plugs, acantholysis, not visible/interrupted DEJ and epidermal bright particles. LC‐OCT increased the diagnostic confidence by 24.7% compared with dermoscopy alone.ConclusionsOur study describes for the first time specific LC‐OCT features of different stages of KC and their histopathological correlates, focusing on keratinocyte morphology and architecture of the epidermis and DEJ. LC‐OCT may open new scenarios in the bedside diagnosis, treatment planning and follow‐up of KC.