Background: Line-field confocal optical coherence tomography is a novel technology able to reproduce a “virtual biopsy” of the skin. The aim of this review is to explore the application of line-field confocal optical coherence tomography (LC-OCT) in various skin diseases, covering skin cancers, inflammatory and infectious skin diseases, genetic diseases, cosmetic procedures, and less common disorders. Methods: Study selection was conducted based on LC-OCT and using pertinent MeSh terms, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines from inception to March 2024; to evaluate the quality and risk of bias of studies, Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used. Results: the search retrieved 154 papers according to the selection criteria; after removing publications by one or more of the exclusion criteria, a total of 96 studies were found to be suitable for the analysis. Conclusions: Increasing evidence supports the use of LC-OCT as an adjunctive diagnostic tool for the in vivo diagnosis of a variety of skin tumors. As this device can be considered a “bridge” between dermoscopy and histopathology, widening applications in numerous fields of clinical dermatology, including inflammatory skin disease treatment, presurgical mapping, cosmetic procedures, and monitoring of non-invasive therapies, have been explored.

Background: Line-field confocal optical coherence tomography (LC-OCT) is an innovative non-invasive imaging technique recently introduced in dermatology. Its use has been established particularly in the diagnosis of skin cancer. The LC-OCT description of basal cell carcinoma (BCC) criteria has served for the conduction of retrospective evaluations on its diagnostic performance, which demonstrated its utility in diagnosis and subtyping BCC. However, prospective studies performed at patients’ bedside are currently lacking in this field. Objective: The objective of the study was to provide parameters of LC-OCT diagnostic performance for BCC derived from a prospective study performed at patients’ bedside. Methods: Lesions clinically equivocal for BCC were prospectively included. Dermoscopic and LC-OCT diagnoses were obtained at the patients’ bedside by an expert observer prior to surgical excision or biopsy. Results: A total of 214 lesions (163 BCCs and 51 BCC imitators) belonging to 119 patients were included. For the differentiation of BCC from BCC-imitators, LC-OCT had the same sensitivity as dermoscopy (98%) but a better specificity (90% vs. 37%). For the discrimination of superficial BCC from other BCC subtypes, LC-OCT had an increased sensitivity and specificity compared to dermoscopy (72% vs. 62%, and 97% vs. 84%, respectively). Conclusions: This prospective study showed that the diagnostic performance for BCC diagnosis and subtyping can be remarkedly increased by LC-OCT compared to dermoscopic examination alone. Our data encourages the inclusion of LC-OCT in the diagnostic process and management of equivocal lesions for BCC.

Background: Hedgehog pathway inhibitors, including sonidegib and vismodegib, represent the treatment strategy for ‘difficult-to-treat’ basal cell carcinoma (BCC), encompassing, among others, locally advanced (laBCC) and metastatic BCC. Assessment of therapy response is challenging due to the presence of telangiectasia and scar tissue at the area of the BCC lesion. Line-field confocal optical coherence tomography (LC-OCT) is a new noninvasive imaging technique that provides high-resolution visualization of skin structures. Objectives: To investigate the value of LC-OCT for the assessment of laBCC response to sonidegib therapy. Methods: We retrospectively included patients with laBCC treated with sonidegib in the period from May 2020 to May 2023. Patients with laBCC underwent LC-OCT at baseline before starting sonidegib, and after sonidegib discontinuation when clinical complete response (CR) was reached. A subset of patients underwent LC-OCT assessment during sonidegib therapy to assess tumour persistence. Results: Twenty laBCCs in 20 patients [4 women, 16 men; mean (SD) age 76 (18) years] treated with oral sonidegib 200 mg daily were included in the study. Ten patients obtained an apparent clinical CR; LC-OCT imaging confirmed CR in 7/10 patients (70%), while in the remaining patients (3/10, 30%) LC-OCT revealed findings indicative of BCC non-CR. Ten patients were continuing sonidegib treatment: in this group LC-OCT revealed findings suggestive of BCC persistence in all 10 patients (100%). Conclusions: In this study we provide preliminary results of the beneficial use of LC-OCT in the management of patients with laBCC treated with sonidegib therapy.