Line-field confocal optical coherence tomography (LC-OCT) is a novel imaging technique for in vivo examination of the skin that has recently been introduced in the dermatologic armamentarium of non-invasive diagnostic tools. Its usefulness in the diagnosis and treatment monitoring of some neoplastic, inflammatory, and infectious skin conditions has been demonstrated. The aim of this study was to evaluate the LC-OCT features of psoriasis in a large number of psoriatic plaques along with their histopathologic correlation. In this retrospective study, the LC-OCT and the corresponding histopathologic images of 100 psoriatic plaques of the trunk, upper and lower arms from 60 patients that underwent both procedures were evaluated and correlated. The following microscopic findings, typical of plaque psoriasis, were observed at both LC-OCT and histopathology: hyperkeratosis, parakeratosis, acanthosis, papillomatosis and vascular changes, Munro microabscesses, and pustules of Kogoj. The LC-OCT findings perfectly matched with histopathology. Our study confirms the usefulness of this new imaging technique in the non-invasive visualization of the common diagnostic clues of psoriasis.

Background: Lichen planus (LP) is a chronic inflammatory disease that can present with significant morbidity, particularly in children. Erosive lichen planus (ELP), its rare destructive subtype, can be particularly difficult to diagnose and manage. We present a rare pediatric case of ELP with multisite involvement and discuss the differential diagnosis. Case Presentation: A 12-year-old boy presented with painful erosions and ulcers on the lateral tongue and dystrophic nails. His six-year history of tongue and nail lesions prompted several comprehensive examinations. Laboratory tests did not reveal any abnormalities. Histopathological examination of the tongue lesions was representative of ELP. Line-field confocal optical coherence tomography (LC-OCT) examination of the tongue lesions showed features that strongly correlated with histopathology. The patient was later hospitalized due to dysphagia and esophageal food impaction, during which esophageal ELP was confirmed. The patient was initially managed with topical corticosteroids. He was later started on systemic therapy in the form of methotrexate and low-dose naltrexone to address his symptoms and disease presentation. Conclusions: This case highlights the complexities of diagnosis and management of ELP in pediatric patients. A multidisciplinary approach and regular follow-up are necessary to manage symptoms, prevent complications, and improve quality of life.

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.

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.

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.

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.

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease. Due to its high prevalence, considerable morbidity, and chronicity, there is a need for the accurate in vivo evaluation of treatment efficacy. Line-field confocal optical coherence tomography (LC-OCT) is a new emerging imaging technique able to perform a non-invasive, real-time examination of the epidermis and the upper dermis. LC-OCT may represent a promising tool in the diagnosis and treatment follow-up of chronic eczematous skin diseases with barrier defects.

We aimed to investigate the role of LC-OCT in the non-invasive monitoring of the treatment effect on five patients with severe atopic dermatitis during dupilumab treatment.

LC-OCT imaging was performed on five patients (three women and two men) aged between 14 and 85 years old at the baseline and at 2, 4, and 6 weeks of treatment with dupilumab. The LC-OCT scans were performed at two sites, the lesional skin in the antecubital fossa and the extensor part of the arm, considered a control site on each patient for comparison. The captured images were later evaluated. Descriptive statistics and a t-test were used to compare the analyzed parameters over time and between involved atopic skin and clinically healthy skin.

The LC-OCT imaging was able to detect the difference in stratum corneum (SC) thickness and quality and epidermal thickness (ET) and the changes before and after treatment with high accuracy. The main findings include a significant reduction in the epidermal and stratum corneum thickness and decreased epidermal spongiosis and inflammation, with better quality of the stratum corneum indicating restoration of its tightness at both lesional and control sites.

This study demonstrates that clinical improvement of affected and unaffected atopic skin under dupilumab treatment correlates with the LC-OCT findings. LC-OCT represents a novel, non-invasive tool examining the in vivo skin barrier and inflammation and can help to monitor the treatment efficacy among patients with atopic dermatitis in daily practice.

Extramammary Paget disease (EMPD) is an uncommon adenocarcinoma of apocrine gland-rich areas, presenting significant diagnostic challenges due to its nonspecific clinical appearance and frequent misidentification as benign, inflammatory skin conditions. Traditional diagnostic methods such as biopsy are invasive and uncomfortable, often required repeatedly due to high recurrence rates. Dermoscopy and non-invasive imaging techniques have been used but provide limited diagnostic accuracy due to their constraints in depth penetration and resolution. Recent advancements in imaging technologies, such as line-field confocal optical coherence tomography (LC-OCT), show promise in enhancing diagnostic precision while minimizing invasive procedures. LC-OCT merges high-resolution imaging with deep penetration capabilities, capturing detailed horizontal and vertical skin images akin to histopathology. This study evaluated the diagnostic performance of LC-OCT in detecting EMPD and its recurrence in 17 clinically suspicious anogenital regions, belonging to six patients. Data were collected prospectively at the patient's bedside by an LC-OCT expert with poor training for EMPD, and, then, reviewed retrospectively by an independent LC-OCT expert with adequate training for EMPD and no concerns about time. The prospective examination yielded 64.7% accuracy (11 true results out of 17 total cases), 71.4% sensitivity (10 true positives out of 14 actual positives), and 33.3% specificity (1 true negative out of 3 actual negatives). The retrospective analysis achieved 94.1% accuracy (16 true results out of 17 total cases), 100% sensitivity (14 true positives out of 14 actual positives), and 66.7% specificity (2 true positives out of 3 actual positives), with the only false positive case being a difficult-to-diagnose concomitant presentation of a lichen sclerosus et atrophicus. Despite the need for specialized training, our results suggest that LC-OCT represents a valuable tool for accurately identifying EMPD and improving its management by reducing unnecessary biopsies. Further studies are needed to standardize its clinical application.

A line-field confocal optical coherence tomography (LC-OCT) combines confocal microscopy and optical coherence tomography into a single, rapid, easy-to-use device. This meta-analysis was performed to determine the reliability of LC-OCT for diagnosing malignant skin tumors. PubMed, EMBASE, Web of Science databases, and the Cochrane Library were searched for research studies in the English language from inception till December 2023. To assess quality and the risk of bias, the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used. The sensitivity and specificity of each study were calculated. The bivariate summary sensitivity and specificity were calculated using the linear mixed model. Five studies with 904 reported per lesion analyses in our study; the specificity and sensitivity ranged from 67% to 97% and 72% to 92%, respectively. The pooled specificity and sensitivity were 91% (95% CI: 76-97%) and 86.9% (95% CI: 81.8-90.8%), respectively. The summary sensitivity and specificity from the bivariate approach are 86.9% (95% CI: 81.8-90.8%) and 91.1% (95% CI: 76.7-97.0%), respectively. The area under the curve is 0.914. LC-OCT shows great sensitivity and specificity in diagnosing malignant skin tumors. However, due to the limited number of studies included in our meta-analysis, it is premature to elucidate the true potential of LC-OCT.

Inflammatory skin diseases, such as psoriasis, atopic eczema, and contact dermatitis pose diagnostic challenges due to their diverse clinical presentations and the need for rapid and precise diagnostic assessment.

While recent studies described non-invasive imaging devices such as Optical coherence tomography and Line-field confocal OCT (LC-OCT) as possible techniques to enable real-time visualization of pathological features, a standardized analysis and validation has not yet been performed.

One hundred forty lesions from patients diagnosed with atopic eczema (57), psoriasis (50), and contact dermatitis (33) were imaged using OCT and LC-OCT. Statistical analysis was employed to assess the significance of their characteristic morphologic features. Additionally, a decision tree algorithm based on Gini's coefficient calculations was developed to identify key attributes and criteria for accurately classifying the disease groups.

Descriptive statistics revealed distinct morphologic features in eczema, psoriasis, and contact dermatitis lesions. Multivariate logistic regression demonstrated the significance of these features, providing a robust differentiation between the three inflammatory conditions. The decision tree algorithm further enhanced classification accuracy by identifying optimal attributes for disease discrimination, highlighting specific morphologic criteria as crucial for rapid diagnosis in the clinical setting.

The combined approach of descriptive statistics, multivariate logistic regression, and a decision tree algorithm provides a thorough understanding of the unique aspects associated with each inflammatory skin disease. This research offers a practical framework for lesion classification, enhancing the interpretability of imaging results for clinicians.

The popularity of tattoos has led to an increase in associated skin reactions, including complications such as infection, allergic reactions and rare conditions such as tattoo-induced cutaneous lymphoid hyperplasia (CLH). CLH is a benign lymphoproliferative reaction with clinical features resembling malignant cutaneous lymphomas. Non-invasive diagnostic tools like reflectance confocal microscopy (RCM) and the new line-field confocal optical coherence tomography (LC-OCT) are being studied in dermatology better to understand the morphological patterns of many dermatological diseases. Between September 2021 and May 2023, patients with suspicious lesions for tattoo-related CLH were analysed using RCM and LC-OCT before confirming the diagnosis of CLH through skin biopsy and histopathological examination. The study included five cases of CLH. It focused on the analysis of high-quality LC-OCT images/videos and RCM images to investigate the features of CLH in tattooed individuals. Most (80%) cases exhibited a mixed T and B lymphocyte infiltration subtype, while 20% showed a predominant T infiltration subtype. RCM and LC-OCT revealed characteristic features, including architectural disarray, fibrosis, lymphoid infiltrates, and pigment deposits in the epidermis and dermis. Non-invasive tools such as RCM and LC-OCT are valuable in diagnosing tattoo-related CLH. While skin biopsy remains the current standard for diagnosis, RCM and LC-OCT can serve as helpful adjuncts in identifying the most representative area for biopsy. They may potentially become alternative diagnostic options in the future, offering benefits in terms of cost, diagnostic efficiency, aesthetics and patient satisfaction as the prevalence of tattoo-related adverse reactions continues to rise.

Hydradermabrasion, also known as "HydraFacial," is an exfoliative cosmetic procedure for skin rejuvenation that has gained popularity. Despite its increasing popularity, clinical studies validating its efficacy with non-invasive assessment of histological changes to the skin, are scarce. In this study, we used Line-Field Confocal Optical Coherence Tomography (LC-OCT), an optical imaging device, to non-invasively visualize microscopic changes to skin anatomy after hydradermabrasion treatment.

Eight volunteers (Fitzpatrick skin types II-V) were recruited for this study. Images, using LC-OCT (DeepLive, DAMAE medical) were obtained before and after hydradermabrasion and at 2 weeks post-treatment. A commercially available hydradermabrasion device was utilized to perform the dermabrasion.

In the epidermis, initially, a decrease in the average thickness of the stratum corneum, from 9.42 to 6.67 µm was visualized in LC-OCT images after hydradermabrasion. However, at 2 weeks of follow-up, the average stratum corneum thickness was 9.75 µm, resulting in an overall increase in the average thickness after treatment. Improved homogenization of the stratum corneum and decreased number of undulations in the epidermis post-treatment were also visualized. In all the subjects, the superficial dermis appeared stretched, which returned to baseline by the 2-week follow-up. At the 2-week follow-up, there were no visible differences in the quality and quantity of collagen fibers in the dermis.

In our study, LC-OCT images of the epidermis and dermis demonstrated microscopic features of skin rejuvenation when treated with hydradermabrasion. Thus, not only highlighting the efficacy of hydradermabrasion but also the potential of LC-OCT to serve as a tool for visualizing the microscopic effects of cosmetic procedures on skin anatomy.

Line-field confocal optical coherence tomography (LC-OCT) is a new, valid means for a rapid and non-invasive in vivo examination of the epidermis and upper dermis, allowing digital interpretation and measurement of high-resolution images on a cellular level. Given these properties, it may represent a valid tool for monitoring psoriasis during treatment, allowing a new method to set a precise objective severity of the disease.

We aimed to investigate the potentialities of LC-OCT in the non-invasive monitoring of microscopical changes associated with moderate-severe plaque psoriasis (PP) during the treatment with the most common biological drugs.

We performed LC-OCT imaging of PP lesions from 17 patients before and after 8 weeks of treatment. The clinical severity of the single lesions was evaluated using a lesion score (LS), designed considering three parameters: erythema, desquamation and infiltration. LC-OCT images were segmented by artificial intelligence and evaluated based on three microscopic criteria: the thickness of the stratum corneum, the thickness of the living epidermis and the undulation of the dermo-epidermal junction.

Line-field confocal optical coherence tomography digital analysis allowed recognition and quantification of the three microscopic criteria, showing a reduction of all these during the follow-up. Furthermore, a high correlation between change in LS and the thickness of the stratum corneum and the thickness of the living epidermis was found.

Line-field confocal optical coherence tomography can non-invasively monitor the response of PP to different treatments. Morphometric changes occurring in the psoriatic lesion during the 8-week treatment period were identified by in vivo LC-OCT and measured by using artificial intelligence. Although future studies are required, based on these preliminary results, LC-OCT may represent a valid potential tool for precise monitoring of therapeutic response.

Superficial Acral fibroma (SAF), also known as osteofibroma, is a rare fibromatous tumor primarily involving superficial soft tissues. Clinically, SAF typically manifests as a slow-growing, solitary, well-defined nodule or mass. Although these lesions are generally asymptomatic, some cases may present with associated pain, often linked to a history of trauma. SAF lesions commonly exhibit hemispherical, polypoid, or warty growths, with occasional occurrences of ulceration and bleeding.The majority of SAFs express CD34 and CD99, but in the two cases we report, there was diffuse expression of CD34 and focal positive expression of CD68. CD68 positivity suggests a propensity for tumor cells to metastasize to secondary sites. Notably, previously reported cases of single SAF did not display positive CD68 expression, indicating a potential association with other aggressive tumors. However, the current clinical and pathological manifestations do not clarify the diagnosis of additional malignant tumors. Consequently, regular postoperative monitoring of the patient from the aforementioned two cases is essential to detect the presence of other malignant tumors. The significance of CD68-positive expression in this case lies in its potential association with such tumors.

The clinical differential diagnosis of lesions arising on the eyelid margin may be challenging and an unneeded surgical approach may have serious functional and aesthetic consequences. Nonetheless, early recognition and treatment of malignant tumors of the eyelid margin is mandatory. Line-field confocal optical coherence tomography (LC-OCT) is a novel tool for the in vivo, real-time skin imaging.

The aim of the study was to identify and analyze the LC-OCT features of a series of eyelid margin growths and to correlate these features with the histopathological findings.

Patients with eyelid margin growths who were scheduled for lesion excision underwent LC-OCT examination. Inclusion criteria were a challenging clinical aspect of the lesions and a clinical history of recent onset (up to 12 months). In all cases, the histopathological examination of the excised lesions was performed for the final diagnosis.

A total of 31 lesions located on the upper (13 cases) or lower (18 cases) eyelid margin from 28 consecutive patients (male = 15, female = 13; mean age: 64.7 years, range: 44-87 years) were evaluated and excised. The histopathologic diagnoses were nodular basal cell carcinoma (BCC) (nine cases), squamous cell carcinoma (SCC) (three cases), compound nevus (four cases), dermal nevus (two cases), seborrheic keratosis (four cases), pyogenic granuloma (one case), trichilemmal cyst (three cases), and hidrocystoma (five cases). LC-OCT allowed the in vivo recognition of the main microscopic features of the examined lesions.

LC-OCT represents a promising tool for the evaluation of eyelid margin lesions. Advantages of non-invasive diagnosis particularly relevant in such a sensitive region include a more correct planning of the treatment and, in case of surgery, the most appropriate surgical approach and, importantly, a correct timing of intervention.

A handheld non-invasive confocal Raman system (CRS) was used to evaluate the differences in skin biochemicals between atopic dermatitis (AD) and psoriasis, which are inflammatory skin conditions. Raman spectral measurements in the fingerprint and high wavenumber region were acquired using a portable in-house CRS system with excitation lasers operating at 671 and 785 nm. It was deduced that relative amount of water decreases in the following sequence of skin: healthy, psoriasis and AD. Moreover, differential trends were observed for the subclasses of ceramides such that ceramide 3 is lower in the lesional AD and psoriasis skin as compared to healthy, while ceramide 2 showed a contrasting trend of decrease in lesional AD and increase in lesional psoriasis as opposed to healthy skin. Amount of cholesterol was significantly higher in lesional psoriasis as compared to lesional AD and healthy skin. These differences can aid in an objective classification of the skin conditions and in the formulation of new disease-specific topical treatments.

Line-field confocal optical coherence tomography (LC-OCT) is a non-invasive optical imaging technique based on a combination of the principles of optical coherence tomography and reflectance confocal microscopy with line-field illumination, which can generate cell-resolved images of the skin in vivo. This article reports on the LC-OCT technique and its application in dermatology. The principle of the technique is described, and the latest technological innovations are presented. The technology has been miniaturized to fit within an ergonomic handheld probe, allowing for the easy access of any skin area on the body. The performance of the LC-OCT device in terms of resolution, field of view, and acquisition speed is reported. The use of LC-OCT in dermatology for the non-invasive detection, characterization, and therapeutic follow-up of various skin pathologies is discussed. Benign and malignant melanocytic lesions, non-melanocytic skin tumors, such as basal cell carcinoma, squamous cell carcinoma and actinic keratosis, and inflammatory and infectious skin conditions are considered. Dedicated deep learning algorithms have been developed for assisting in the analysis of LC-OCT images of skin lesions.

Psoriasis is an immune-mediated disease with a strong genetic component that brings many challenges to sick individuals, such as chronic illness, and which has multiple associated comorbidities like cardiovascular disease, metabolic syndrome, inflammatory bowel disease, and psychological disorders. Understanding the interplay between the innate and adaptative immune system has led to the discovery of specific cytokine circuits (Tumor Necrosis Factor-alpha (TNF-α), IL-23, IL-17), which has allowed scientists to discover new biomarkers that can be used as predictors of treatment response and pave the way for personalized treatments. In this review, we describe the footprint psoriasis leaves on the skin and beyond, key pathophysiological mechanisms, current available therapeutic options, and drawbacks faced by existing therapies, and we anticipate potential future perspectives that may improve the quality of life of affected individuals.

Line-field confocal optical coherence tomography (LC-OCT) can help the clinical diagnosis of skin diseases. The present study aimed to evaluate the sensitivity, specificity, and diagnostic accuracy of LC-OCT for the diagnosis of the most frequent non-melanoma skin cancers (NMSCs), i.e., basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Comparing LC-OCT diagnostic performances with those of dermoscopy, histopathological examination was used as a gold standard. For every study endpoint, the diagnostic ability of LC-OCT revealed superiority over the dermoscopic examination. In particular, a significant increase in specificity was observed. Sensitivity, specificity, and diagnostic accuracy of dermoscopy and LC-OCT for the diagnosis of malignancy were, respectively, 0.97 (CI 0.94-0.99), 0.43 (CI 0.36-0.51), and 0.77 (CI 0.72-0.81) for dermoscopy and 0.99 (CI 0.97-1.00), 0.90 (CI 0.84-0.94), and 0.96 (CI 0.93-0.97) for LC-OCT. The positive predictive value (PPV) resulted in 0.74 (CI 0.69-0.78) for dermoscopy and 0.94 (CI 0.91-0.97) for LC-OCT, and the negative predictive value (NPV) was 0.89 (CI 0.81-0.95) for dermoscopy and 0.98 (CI 0.95-1.00) for LC-OCT. Finally, our real-life study showed a potentially important role of LC-OCT in the non-invasive diagnosis of NMSCs, especially BCC. The real-time imaging technique could spare unnecessary biopsies with an increased sensitivity, a much higher specificity, and better accuracy than clinical assessment with dermoscopy alone.

Line-field confocal optical coherence tomography (LC-OCT) is a new, noninvasive imaging technique for the diagnosis of skin cancers. A total of 243 benign (54%) and malignant (46%) skin lesions were consecutively enrolled from 27 August 2020, to 6 October 2021 at the Dermatology Department of the University Hospital of Siena, Italy. Dermoscopic- and LC-OCT-based diagnoses were given by an expert dermatologist and compared with the ground truth. Considering all types of malignant skin tumours (79 basal cell carcinomas (BCCs), 22 squamous cell carcinomas, and 10 melanomas), a statistically significant increase (p = 0.013) in specificity was observed from dermoscopy (0.73, CI 0.64-0.81) to LC-OCT (0.87, CI 0.79-0.93) while sensitivity was the same with the two imaging techniques (0.95 CI 0.89-0.98 for dermoscopy and 0.95 CI 0.90-0.99 for LC-OCT). The increase in specificity was mainly driven by the ability of LC-OCT to differentiate BCCs from other diagnoses. In conclusion, our real-life study showed that LC-OCT can play an important role in helping the noninvasive diagnosis of malignant skin neoplasms and especially of BCCs. LC-OCT could be positioned after the dermoscopic examination, to spare useless biopsy of benign lesions without decreasing sensitivity.

Palmoplantar psoriasis (PP) is a relatively uncommon variant of psoriasis that affects palms and soles, and that frequently shares both clinical and histologic features with chronic eczema, hyperkeratotic hand dermatitis and allergic contact dermatitis. The present study aims to characterize the histologic features of PP on a series of 21 cases. The following morphological features and their distribution were included: parakeratosis, dilated vessels in papillary dermis, psoriasiform acanthosis with elongation of rete ridges, perivascular lymphocytic infiltrate, decrease/loss of granular layer, Munro's microabscesses, spongiform pustules of Kogoj, spongiosis and lymphocytic exocytosis. The main diagnostic clues and histologic differential diagnoses are also discussed.