Multicentre study on inflammatory skin diseases from The International Confocal Working Group: specific confocal microscopy features and an algorithmic method of diagnosis

Real-life practice of reflectance confocal microscopy in France: A prospective multicenter study

BACKGROUND

Studies demonstrating the potential utility of reflectance confocal microscopy (RCM) have been performed under experimental conditions.

OBJECTIVE

To provide an overview of RCM practice in real-life.

METHODS

A multicenter, prospective study carried out in 10 university dermatology departments in France.

RESULTS

Overall, 410 patients were enrolled. One-half of the patients (48%) were referred by private practice dermatologists. They were referred for diagnosis (84.9%) or presurgical mapping (13%). For diagnosis, the lesions were located on the face (62%), arms and legs (14.9%), and trunk (13.6%), and presurgical mapping was almost exclusively on the face (90.9%). Among those referred for diagnosis, the main indication was suspicion of a skin tumor (92.8%). Of these, 50.6% were spared biopsies after RCM. When RCM indicated surgery, histology revealed malignant lesions in 72.7% of cases. The correlation between RCM and histopathology was high, with a correlation rate of 82.76% and a kappa coefficient of 0.73 (0.63; 0.82).

LIMITATIONS

This study was performed in the settings of French tertiary referral hospitals.

CONCLUSION

This study shows that in real-life RCM can be integrated into the workflow of a public private network, which enables a less invasive diagnostic procedure for patients.

Preliminary Evaluation of in vivo Reflectance Confocal Microscopy Features of Neonatal Lupus Erythematosus

INTRODUCTION

Neonatal lupus erythematosus (NLE) is a rare autoimmune disease, which needs to be distinguished from eczema, congenital syphilis, and tinea corporis in newborns. Reflectance confocal microscopy (RCM) could be a helpful noninvasive diagnostic tool, which has been used to evaluate several inflammatory skin conditions. The aim of this study was to describe the RCM characteristics of NLE.

METHODS

Eleven NLE patients were included in the study, and all patients were evaluated clinically with RCM. We also evaluated RCM images from 11 eczema patients as controls.

RESULTS

Some major key diagnostic features of NLE can be observed by RCM: an enlarged honeycomb pattern (9/11, 81.8%), round-to-oval cyst-like structures were present (6/11, 54.5%), the normal ring-like structures were totally or partially obliterated (11/11, 100%) at the level of the dermo-epidermal junction, medium refractivity collagen fibers that were disorganized (10/11, 90.9%), numerous high refractivity round cells (11/11, 100%) in the dermis.

CONCLUSION

RCM allows the visualization of major key diagnostic features of NLE and serves as a complementary diagnostic tool for NLE.

Hyperspectral imaging to accurately segment skin erythema and hyperpigmentation in cutaneous chronic graft-versus-host disease

In 51 lesions from 15 patients with the inflammatory skin condition chronic graft-versus-host-disease, hyperspectral imaging accurately delineated active erythema and post-inflammatory hyperpigmentation. The method was validated by dermatologist-approved confident delineations of only definitely affected and definitely unaffected areas in photographs. A prototype hyperspectral imaging system acquired a 2.5 × 3.5 cm2 area of skin at 120 wavelengths in the 450-850 nm range. Unsupervised extraction of unknown absorbers by endmember analysis achieved a comparable accuracy to that of supervised extraction of known absorbers (melanin, hemoglobin) by chromophore mapping: 0.78 (IQR: 0.39-0.85) vs. 0.83 (0.53-0.91) to delineate erythema and 0.74 (0.57-0.87) vs. 0.73 (0.52-0.84) to delineate hyperpigmentation. Both algorithms achieved higher specificity than sensitivity. Whereas a trained human confidently marked a median of 7% of image pixels, unsupervised and supervised algorithms delineated a median of 14% and 27% pixels. Hyperspectral imaging could overcome a fundamental practice gap of distinguishing active from inactive manifestations of inflammatory skin disease.

Association of Leukocyte Adhesion and Rolling in Skin With Patient Outcomes After Hematopoietic Cell Transplantation Using Noninvasive Reflectance Confocal Videomicroscopy

Importance

Hematopoietic cell transplantation (HCT) is a potential cure for hematologic cancer but is associated with a risk of relapse and death. Dynamic biomarkers to predict relapse and inform treatment decisions after HCT are a major unmet clinical need.

Objective

To identify a quantitative characteristic of leukocyte-endothelial interactions after HCT and test its associations with patient outcomes.

Design, Setting, and Participants

In this prospective single-center cohort study from June 2017 to January 2020, patients of any age, sex, race, and ethnicity who had HCT for hematologic cancer were referred by health care professionals as either suspected of having symptoms or not having symptoms of acute graft-vs-host disease between 25 and 161 days after HCT. Patients underwent noninvasive skin videomicroscopy. Videos of dermal microvascular flow were recorded with a reflectance confocal microscope. Two blinded observers (J.R.P. and Z.Z.) counted leukocytes adherent to and rolling along the vessel wall per hour (A&R). Of 57 enrolled patients, 1 relapsed before imaging and was excluded, resulting in 56 patients included in analyses.

Main Outcomes and Measures

Relapse of cancer, relapse-free survival, and overall survival.

Results

Among the 56 patients (median age, 59 years; 38 [68%] male) who underwent imaging a median of 40 days after HCT, 21 had high A&R and 35 had low A&R. After correcting for the revised Disease Risk Index, patients with high A&R had higher rates of relapse (hazard ratio [HR], 4.24; 95% CI, 1.32-13.58; P = .02), reduced relapse-free survival (HR, 3.29; 95% CI, 1.26-8.55; P = .02), and reduced overall survival (HR, 3.06, 95% CI, 1.02-9.19; P = .05). These associations were preserved after correcting for possible confounders, steroid treatment, and acute graft-vs-host disease status. In the prognostic adequacy calculation by using Cox models, the new imaging biomarker (A&R) accounted for 82% to 95% of the prognostic information to predict each outcome. By contrast, the best existing clinical predictor routinely available, the revised Disease Risk Index, accounted for 10% to 28% of the prognostic information in the same model.

Conclusions and Relevance

In this cohort study, leukocyte-endothelial interactions, visualized directly in skin after HCT, were associated with the patient outcomes of relapse, relapse-free survival, and overall survival. Assessing this dynamic marker could help patients at high risk for relapse who may benefit from interventions, such as early withdrawal of immunosuppression.

In Vivo Reflectance Confocal Microscopy of Cutaneous Acute Graft-Versus-Host Disease: Concordance with Histopathology and Interobserver Reproducibility of a Glossary with Representative Images

BACKGROUND

The reliability to noninvasively identify features of inflammatory dermatoses by reflectance confocal microscopy (RCM) remains unknown. Lack of formal training among RCM readers can result in inconsistent assessments, limiting clinical utility. Specific consensus terminology with representative images is necessary to ensure consistent feature-level interpretation among RCM readers.

OBJECTIVES

(1) Develop a glossary with representative images of RCM features of cutaneous acute graft-versus-host disease (aGVHD) for consistent interpretation among observers, (2) assess the interobserver reproducibility among RCM readers using the glossary, and (3) determine the concordance between RCM and histopathology for aGVHD features.

METHODS

Through an iterative process of refinement and discussion among five international RCM experts, we developed a glossary with representative images of RCM features of aGVHD. From April to November 2018, patients suspected of aGVHD were imaged with RCM and subsequently biopsied. 17 lesions from 12 patients had clinically and pathologically confirmed cutaneous aGVHD. For each of these lesions, four dermatopathologists and four RCM readers independently evaluated the presence of aGVHD features in scanned histopathology slides and 1.5x1.5 mm RCM submosaics at 4 depths (blockstacks), respectively. RCM cases were adjudicated by a fifth RCM expert. Interobserver reproducibility was calculated by U statistic. Concordance between modalities was determined by fraction agreement.

RESULTS

We present a glossary with representative images of 18 aGVHD features by RCM. The average interobserver reproducibility among RCM readers (75%, confidence interval, CI: 71%-79%) did not differ significantly from dermatopathologists (80%, 76%-85%). The concordance between RCM and histopathology was 59%.

CONCLUSIONS

By using the glossary, the interobserver reproducibility among RCM readers was similar to the interobserver reproducibility among dermatopathologists. There was good concordance between RCM and histopathology to visualize aGVHD features. The implementation of RCM can now be advanced in a variety of inflammatory conditions with a validated glossary and representative image set.

Ex Vivo Fluorescence Confocal Microscopy in Specimens of the Liver: A Proof-of-Concept Study

Ex vivo Fluorescence Confocal Microscopy (FCM) is a technique providing high-resolution images of native tissues. The method is increasingly used in surgical settings in areas of dermatology and urology. Only a few publications exist about examinations of tumors and non-neoplastic lesions of the liver. We report on the application of FCM in biopsies, surgical specimens and autopsy material (33 patients, 39 specimens) of the liver and compare the results to conventional histology. Our preliminary examinations indicated a perfect suitability for tumor diagnosis (ĸ = 1.00) and moderate/good suitability for the assessment of inflammation (ĸ = 0.4-0.6) with regard to their severity and localization. Macro-vesicular steatosis was reliably detected, micro-vesicular steatosis tended to be underestimated. Cholestasis and eosinophilic granules in granulocytes were not represented in the scans. The tissue was preserved as native material and maintained its quality for downstream histological, immunohistological and molecular examinations. In summary, FCM is a material sparing method that provides rapid feedback to the clinician about the presence of tumor, the degree of inflammation and structural changes. This can lead to faster therapeutic decisions in the management of liver tumors, treatment of hepatitis or in liver transplant medicine.

Real-Time Reflectance Confocal Microscopy of Cutaneous Graft-versus-Host Disease Correlates with Histopathology

Reflectance confocal microscopy (RCM) allows noninvasive, real-time evaluation of the skin at a resolution akin to histopathology (HP), but its application in cutaneous graft-versus-host disease (GVHD) has not been extensively assessed. We describe RCM features of cutaneous GVHD including acute (aGVHD), late acute, chronic (cGVHD; sclerotic and nonsclerotic subtypes), and inactive GVHD and correlate RCM with same-site HP for a subset of patients. Thirty-two adult and pediatric allogeneic hematopoietic cell transplantation (allo-HCT) recipients with cutaneous GVHD received RCM imaging of ≥1 lesions (n = 44), 13 of which necessitated skin biopsy. RCM images were deidentified and assessed by 2 RCM experts blinded to clinical and HP findings to reach a consensus on the features and patterns of the inflammatory dermatoses. Major RCM features (present in ≥65% of lesional sites) and patterns were reported. To determine the correlation between RCM and HP, detection of cellular features and patterns of inflammatory dermatoses were compared using percent agreement and prevalence-adjusted, bias-adjusted kappa estimates. Seven patients with early or late aGVHD (7 lesions) had irregular honeycombing, spongiosis, dermoepidermal junction (DEJ) and dermal inflammation, and melanophages; those with early aGVHD also had hyperkeratosis, dilated vessels, and coarse connective tissue. Both groups had an interface dermatitis pattern. Eighteen patients with nonsclerotic cGVHD (24 lesions) had irregular honeycombing, spongiosis, DEJ and dermal inflammation, dilated vessels, coarse connective tissue, and interface and spongiotic dermatitis patterns. Three sclerotic patients with cGVHD (7 lesions) had irregular honeycombing, DEJ and dermal inflammation with an interface dermatitis pattern. Four patients with inactive GVHD (6 lesions) showed minimal inflammation. RCM and HP had similar detection rates for 6 of 13 features and overall patterns important for diagnosis in 2 patients with late aGVHD (2 lesions; 15%) and 10 with nonsclerotic cGVHD (11 lesions; 85%) necessitating skin biopsy. RCM can detect features commonly reported in cutaneous GVHD and is comparable to HP. Additional characterization of cutaneous GVHD by RCM may enable future use in diagnosing, monitoring, or predicting disease in real time.

In Vivo Reflectance Confocal Microscopy as a Response Monitoring Tool for Actinic Keratoses Undergoing Cryotherapy and Photodynamic Therapy

Simple Summary

The assessment of actinic keratoses (AKs) in prevention and therapeutic trials, as well as clinical practice, could significantly benefit from the incorporation of non-invasive imaging technology. Such technology has the potential to enhance the objective evaluation of clinical and subclinical AKs with the added advantage of sequential monitoring. In vivo reflectance confocal microscopy (RCM) allows for the non-invasive imaging of AKs at a cellular level. We aimed to establish an in in vivo RCM protocol for AK response monitoring, ultimately leading to more reliable characterization of longitudinal responses and therapy optimization.

Abstract

Reflectance confocal microscopy (RCM) presents a non-invasive method to image actinic keratosis (AK) at a cellular level. However, RCM criteria for AK response monitoring vary across studies and a universal, standardized approach is lacking. We aimed to identify reliable AK response criteria and to compare the clinical and RCM evaluation of responses across AK severity grades. Twenty patients were included and randomized to receive either cryotherapy (n = 10) or PDT (n = 10). Clinical assessment and RCM evaluation of 12 criteria were performed in AK lesions and photodamaged skin at baseline, 3 and 6 months. We identified the RCM criteria that reliably characterize AK at baseline and display significant reduction following treatment. Those with the highest baseline odds ratio (OR), good interobserver agreement, and most significant change over time were atypical honeycomb pattern (OR: 12.7, CI: 5.7–28.1), hyperkeratosis (OR: 13.6, CI: 5.3–34.9), stratum corneum disruption (OR: 7.8, CI: 3.5–17.3), and disarranged epidermal pattern (OR: 6.5, CI: 2.9–14.8). Clinical evaluation demonstrated a significant treatment response without relapse. However, in grade 2 AK, 10/12 RCM parameters increased from 3 to 6 months, which suggested early subclinical recurrence detection by RCM. Incorporating standardized RCM protocols for the assessment of AK may enable a more meaningful comparison across clinical trials, while allowing for the early detection of relapses and evaluation of biological responses to therapy over time.

Dermoscopy, confocal microscopy and optical coherence tomography features of main inflammatory and autoimmune skin diseases: A systematic review

BACKGROUND/OBJECTIVES

Non-invasive skin imaging features of main skin inflammatory and autoimmune diseases have been reported, although a comprehensive review of their correlation with histopathologic features is currently lacking. Therefore, the aim of this paper was to review the correlation of dermoscopic, reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) criteria of main inflammatory and autoimmune skin diseases with their corresponding histopathologic criteria correlation.

METHODS

Studies on human subjects affected by main inflammatory and autoimmune diseases, defining the correlation of dermoscopic, RCM or OCT with histopathologic criteria, were included in the review. Five groups of diseases were identified and described: psoriasiform, spongiotic and interface dermatitis, bullous diseases and scleroderma.

RESULTS

Psoriasiform dermatitis was typified by white scales, corresponding to hyperkeratosis, and vessels, observed with RCM and OCT. Spongiosis, corresponding to dark areas within the epidermis with RCM and OCT, was the main feature of spongiotic dermatitis. Interface dermatitis was characterised by dermoepidermal junction obscuration. Blisters, typical of bullous diseases, were visualised as dark areas with RCM and OCT while scleroderma lesions were characterised by dermoscopic fibrotic beams, related to dermal thickness variations, with specific OCT and histopathologic correlations.

CONCLUSIONS

Although the role of RCM and OCT has yet to be defined in clinical practice, non-invasive skin imaging shows promising results on inflammatory and autoimmune skin diseases, due to the correlation with histopathologic features.

Clinical Applications of In Vivo and Ex Vivo Confocal Microscopy

Confocal laser scanning microscopy (CLSM) has been introduced in clinical settings as a tool enabling a quasi-histologic view of a given tissue, without performing a biopsy. It has been applied to many fields of medicine mainly to the skin and to the analysis of skin cancers for both in vivo and ex vivo CLSM. In vivo CLSM involves reflectance mode, which is based on refractive index of cell structures serving as endogenous chromophores, reaching a depth of exploration of 200 μm. It has been proven to increase the diagnostic accuracy of skin cancers, both melanoma and non-melanoma. While histopathologic examination is the gold standard for diagnosis, in vivo CLSM alone and in addition to dermoscopy, contributes to the reduction of the number of excised lesions to exclude a melanoma, and to improve margin recognition in lentigo maligna, enabling tissue sparing for excisions. Ex vivo CLSM can be performed in reflectance and fluorescent mode. Fluorescence confocal microscopy is applied for “real-time” pathological examination of freshly excised specimens for diagnostic purposes and for the evaluation of margin clearance after excision in Mohs surgery. Further prospective interventional studies using CLSM might contribute to increase the knowledge about its application, reproducing real-life settings.

Real-Time Confocal Imaging for Hidradenitis Suppurativa: Description of Morphological Aspects and Focus on the Role of Follicular Ostia

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory skin disease involving the follicular unit. Growing evidence suggests a crucial role of hyperkeratosis, infundibular plugging and perifolliculitis in its pathogenesis.

OBJECTIVES

To characterize the microscopic morphology of open comedos using in vivo reflectance confocal microscopy (RCM) and define alterations occurring in HS normal-appearing perilesional skin compared to healthy skin of a control group, discussing therefore microscopic differences.

MATERIALS AND METHODS

Twenty patients (11 males, 9 females; aged 19-51 years) affected by HS were recruited. RCM was performed on open comedos of axillary/inguinal regions and on normal-appearing skin areas distant at least 1.5 cm from HS lesions. Ten healthy individuals (6 males, 4 females) were included as control group.

RESULTS

RCM aspects of 78 open comedos were explored, observing circular/ovoidal structures disclosing a hyperrefractive amorphous material (72/78, 92.3%) within the infundibular cavity surrounded with a bright (51/78, 65.4%) and regular (52/78, 66.2%) border. Follicular ostia of HS perilesional skin (n = 541) compared to follicular ostia of a control group (n = 321) were characterized by a larger infundibular diameter (183.4 vs. 85.8 µm) and diverged in terms of material collected inside infundibula (44.5 vs. 21%) and keratinization of the border (47.6 vs. 25.5%).

CONCLUSION

In vivo characterization of open comedos and the recognition of microscopic subclinical alterations of HS normal-appearing skin, compared to healthy skin, could add further insights into the definition of biological events leading to HS manifestations, including the dysregulated process of keratinization.

Reflectance Confocal Microscopy, Optical Coherence Tomography, and Multiphoton Microscopy in Inflammatory Skin Disease Diagnosis

BACKGROUND AND OBJECTIVES

Technological advances in medicine have brought about many novel skin imaging devices. This review aims to evaluate the scientific evidence supporting the use of noninvasive optical imaging techniques to aid in the diagnosis and prognosis of inflammatory skin diseases.

STUDY DESIGN/MATERIALS AND METHODS

PubMed and Scopus were searched in September 2020 according to PRISMA guidelines for articles using reflectance confocal microscopy (RCM), optical coherence tomography (OCT), and multiphoton microscopy (MPM) in inflammatory skin diseases, excluding studies monitoring treatment efficacy.

RESULTS

At the time of the study, there were 66 articles that addressed the utilization of noninvasive imaging in interface, spongiotic, psoriasiform, vesiculobullous, and fibrosing/sclerosing inflammatory skin dermatoses: RCM was utilized in 46, OCT in 16, and MPM in 5 articles. RCM was most investigated in psoriasiform dermatoses, whereas OCT and MPM were both most investigated in spongiotic dermatoses, including atopic dermatitis and allergic contact dermatitis.

CONCLUSIONS

There is preliminary evidence to support the diagnostic potential of noninvasive optical imaging techniques in inflammatory skin diseases. Improvements in the devices and further correlation with histology will help broaden their utility. Additional studies are needed to determine the parameters for diagnostic features, disease differentiation, and staging of inflammatory skin conditions. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Non-invasive clinical and microscopic evaluation of the response to treatment with clobetasol cream vs. calcipotriol/betamethasone dipropionate foam in mild to moderate plaque psoriasis: an investigator-initiated, phase IV, unicentric, open, randomized clinical trial

BACKGROUND

Treatment response for psoriasis is typically evaluated using clinical scores. However, patients can relapse after clinical clearance, suggesting persistent inflammation. Dermoscopy, reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) can non-invasively improve treatment response assessment.

OBJECTIVES

To compare the clinical and non-invasive microscopic features in a psoriatic target lesion treated with clobetasol cream or calcipotriol/betamethasone dipropionate foam (Cal/BD foam).

METHODS

Prospective, unicentric, open, randomized clinical trial comparing clinical data [total clinical score (TCS)] and microscopic data (dermoscopy, RCM and OCT) in psoriasis patients treated with clobetasol or Cal/BD foam.

RESULTS

We included 36 adult patients (22 men). At week 4, more patients treated with Cal/BD foam achieved TCS ≤1 than with clobetasol (63.2% vs. 18.8%, P = 0.016). Treatment satisfaction was higher with Cal/BD foam (P < 0.03). Microscopically, Cal/BD foam induced more reduction in epidermal thickness at week 4 (P < 0.049). Dilated horizontal blood vessels were more common with clobetasol than with Cal/BD foam at week 8 (69.2% vs. 31.2%, P = 0.159). If epidermal hyperplasia was noted at baseline, the response was poorer with clobetasol (P = 0.029).

LIMITATIONS

Small sample size, open study, imaging sampling bias.

CONCLUSION

Cal/BD foam is more effective than clobetasol, has better patient satisfaction and induces greater reduction in the hyperkeratosis/acanthosis, regardless of baseline epidermal hyperplasia.

In Vivo Reflectance Confocal Microscopy in General Dermatology: How to Choose the Right Indication

Reflectance confocal microscopy (RCM) is a high-resolution, noninvasive imaging technique being increasingly used as an aid to diagnosis in the dermatology setting. RCM is applied in the diagnosis of both melanoma and nonmelanoma skin tumors, but also in the interpretation and management of inflammatory skin diseases. Two different devices with different designs for specific indications are available in the market: a static and a handheld probe. Several clinical presentations of the lesion could affect the examination, such as the presence of ulceration or hyperkeratosis; moreover, the anatomical site can drive the probe selection as well as the effective indication to RCM examination. In this review article, indications for the use of RCM are described in detail with a schematic approach for practical purposes.

Reflectance Confocal Microscopy Applied to Folliculitis Decalvans: Preliminary Results of a Multicenter Study

Although trichoscopic criteria indicative of disease severity and inflammatory activity have been recently proposed, the potential use of reflectance confocal microscopy (RCM) in the evaluation of the inflammatory stage of FD has never been published to date. Our study investigated RCM features of 14 patients with a histopathological diagnosis of FD, evaluating clinical and trichoscopic findings. RCM findings were divided into 2 main patterns: “follicular” and “interfollicular.” Our results suggest a potential role for RCM as a noninvasive, fast technique for a complementary investigation in the diagnostic process, as well as in the therapeutic management decision.

[Reflectance confocal microscopy in Shiitake dermatitis]

Shiitake dermatitis usually occurs 1-2 days after consumption of incompletely cooked or raw shiitake mushrooms and is characterized by linear, pruritic, erythematous papulovesicular rashes. It is caused by lentinan, a polysaccharide component of the cell walls of shiitake mushrooms. The histological examination showed an eczema-like morphology with spongiosis and lymphohistiocytic infiltrates. The results of reflectance confocal microscopy (RCM) correlated with the histopathological investigations. Therefore, RCM can be used for non-invasive diagnostic confirmation of Shiitake dermatitis in the future.

Noninvasive Skin Barrier Assessment: Multiparametric Approach and Pilot Study

The epidermal barrier function is disrupted in various inflammatory skin diseases. Accurate methods to measure skin barrier function are needed to assess the effect of therapeutic agents. Therefore, we developed a noninvasive multiparametric approach to measure four different parameters regarding the skin barrier. In the current pilot study, we evaluate this method in 14 healthy volunteers. We assessed erythema, transepidermal water loss (TEWL), water content, and epidermal thickness at both cheeks before and 30 min after application of Lanette and Vaseline-Lanette cream. For this, we used spectrophotometry, the Aquaflux device, the Epsilon device, and reflection confocal microscopy, respectively. Stratum corneum (SC) thickness was significantly increased after application of both creams (p < 0.05), and this increase was larger after Lanette cream compared to after Vaseline-Lanette cream (p = 0.035). Erythema, TEWL, and water content did not significantly change after cream application. Our multiparametric approach is promising and offers a feasible and practical way to quickly obtain multifaceted information about skin barrier function. Further exploration of this approach after prolonged use of cream and in conditions of disrupted skin barrier are recommended areas for future research.

Introduction to reflectance confocal microscopy and its use in clinical practice

Reflectance confocal microscopy (RCM) is a novel technology that provides noninvasive, in vivo imaging of the skin at nearly histologic resolution. In 2016, the US Centers for Medicare and Medicaid Services (CMS) established reimbursement codes for RCM image acquisition and for the reading and interpretation of images. The combination of RCM imaging with dermoscopy has improved the accuracy of skin cancer diagnosis while reducing the number of biopsies of benign skin lesions. With that, we are starting to see more dermatologists and dermatopathologists using RCM in clinical practice. This editorial is to serve as an introduction on RCM imaging with a focus on its usefulness in both the diagnosis and management of skin cancers. We end by briefly describing the characteristic RCM features of normal skin to serve as a building block for later cases that will explore both the benefits and drawbacks of incorporating RCM imaging for benign and malignant lesions.

Comparison of biophysical, biomechanical and ultrasonographic properties of skin in chronic dermatitis, psoriasis and lichen planus

Background: Skin biometrology is a useful method for evaluation of inflammatory skin disorders such as dermatitis, psoriasis, and lichen planus. The current study tries to compare the biophysical features of skin in dermatitis, psoriasis, and lichen planus.

Methods: By a convenient sampling method, 22 mild to moderate chronic dermatitis, 26 psoriasis, and 21 lichen planus patients were recruited in the study. Stratum corneum (S.C.) hydration, Transepidermal water loss (TEWL), pH, erythema, melanin, sebum, friction, elasticity parameters (R0, R2, and R5), skin temperature, skin thickness, and echo-density of epidermis and dermis were measured on the lesional (selected active lesion), uninvolved perilesional, and uninvolved symmetrical skin. The average of perilesional and symmetrical uninvolved parameters was used as control, while the percentage change of each parameter [(lesion – control / control) ×100] was calculated, and compared among three diseases by ANOVA test using SPSS software version 18. The significance level was set at α=0.05.

Results: Comparison of percentage changes showed that the changes in TEWL, friction index, sebum content, R2 (gross elasticity), R5 (net elasticity), skin temperature, dermal thickness, and epidermal density are not significantly different among three skin diseases. But there were significant differences in three diseases considering the decrease in S.C. hydration (p<0.001), R0 (opposed to firmness) (p<0.001), and dermal density (p<0.001) compared to control skin. Moreover, the increase in skin pH (p<0.001), melanin content (p=0.048), erythema (p=0.023), and epidermal thickness (p <0.001) significantly differed among these diseases.

Conclusion: Dermatitis, psoriasis and lichen planus lesions had specific biophysical changes. It may be helpful in their differential diagnosis.

Noninvasive diagnosis in dermatology

In addition to dermoscopy, there are other imaging and biophysical methods for the noninvasive diagnosis of skin lesions. Confocal laser microscopy allows for high-resolution imaging of the epidermis and upper dermis. It is particularly suitable in the differential diagnosis of melanocytic lesions. Optical coherence tomography (OCT) has a lower resolution compared to confocal laser microscopy but a greater depth of penetration. It is primarily used for imaging epithelial skin cancer, especially in the context of monitoring the effectiveness of nonsurgical therapies. Electrical impedance spectroscopy does not yield cutaneous images but rather provides a score based on the cellular irregularity of the skin. Multispectral analysis involves illumination of the skin with different wavelengths and likewise results in the computation of a score. Both methods are used in the differentiation of dysplastic nevi from melanoma. Other diagnostic imaging and biophysical methods are currently still in the developmental stages. By increasing the sensitivity and specificity of clinical and dermoscopic findings, the aforementioned methods bring about an improvement in noninvasive diagnosis. They allow for skin lesions to be monitored over time and therapeutic effects to be quantified. Finally, they facilitate early diagnosis of skin cancer, and help avoid unnecessary surgery of benign lesions.

Dermatoscopy and Reflectance Confocal Microscopy Correlations in Nonmelanocytic Disorders

Dermatoscopy and in vivo reflectance confocal microscopy are noninvasive techniques that provide a horizontal approach, with an en face view of the skin structures. Both techniques assist in the clinical diagnosis of a variety of inflammatory and infectious cutaneous disorders. In many cases, they have shown concordance. Their combined use represents, in several instances, a promising option to reach the final diagnosis without the need for invasive procedures.

Reflectance confocal microscopy features of thin versus thick melanomas

BACKGROUND

In-vivo reflectance confocal microscopy (RCM) plays an increasingly important role in differential diagnosis of melanoma. The aim of the study was to assess typical confocal features of thin (≤1 mm according to Breslow index) versus thick (>1mm) melanomas.

METHODS

Thirty patients with histopathologically confirmed cutaneous melanoma were included in the study. RCM was performed with Vivascope equipment prior to excision. Fifteen melanomas were thin (Breslow thickness ≤1 mm) and 15 were thick (Breslow thickness >1 mm).

RESULTS

In the RCM examination, the following features were more frequently observed in thin compared to thick melanomas: edged papillae (26.7% vs. 0%, P=0.032) and areas with honeycomb or cobblestone pattern (33.3% vs. 6.7%, P=0.068). Both features are present in benign melanocytic lesions, so in melanoma are good prognostic factors. The group of thick melanomas compared to the group of thin melanomas in the RCM images presented with greater frequency of roundish cells (100% vs. 40%, P=0.001), non-edged papillae (100% vs. 60%, P=0.006), numerous pagetoid cells (73.3% vs. 33.3%, P=0.028), numerous atypical cells at dermal-epidermal junction (53.3% vs. 20%, P=0.058) and epidermal disarray (93.3% vs. 66.7%, P=0.068).

CONCLUSIONS

Non-invasive imaging methods helps in deepening of knowledge about the evolution and biology of melanoma. The most characteristic features for thin melanomas in confocal examination are: fragments of cobblestone or honeycomb pattern and edged papillae (as good prognostic factors). The features of thick melanomas in RCM examination are: roundish cells, non-edged papillae, numerous pagetoid cells at dermal-epidermal junction and epidermal disarray.

Dermoscopic and reflectance confocal microscopy features of cutaneous squamous cell carcinoma

BACKGROUND

Squamous cell carcinoma (SCC) of the skin is a highly prevalent neoplasm. The management and the prognosis of this tumour are dependent on its invasiveness and its grade of differentiation.

OBJECTIVES

To evaluate whether specific dermoscopic and reflectance confocal microscopy (RCM) criteria can predict the diagnosis of invasive SCC vs. in situ SCC and poorly differentiated compared with well- and moderately differentiated SCC.

METHODS

Dermoscopic and RCM images of SCC were retrospectively evaluated for the presence of predefined criteria.

RESULTS

Among 143 SCCs, 121 cases had a complete set of images and thus were included in the study set. The head and neck area was the most frequently involved body site (74/121; 61.1%) followed by extremities (36/121, 29.7%) and trunk (11/121, 9.1%). Seventy tumours were in situ (57.8%), while 51 were invasive (42.1%), of these 11 were poorly differentiated (21.5%), 16 were moderately differentiated (31.3%), and 24 were well differentiated (47.0%). Chi-squared analysis demonstrated that invasive SCCs were characterized by polymorphic vessels, erosion/ulceration, architectural disarrangement, speckled nucleated cells in the dermis, irregularly dilated vessels and absence of hyperkeratosis. Buttonhole vessels, white structureless areas and dotted or glomerular vessels were significantly associated with in situ lesions. Poorly differentiated SCCs were typified by red areas, erosion/ulceration and architectural disarrangement. Well- or moderately differentiated SCCs were associated with white areas and speckled nucleated cells in the epidermis.

CONCLUSION

Clinical, dermoscopic and RCM images provide useful information that should be integrated in order to achieve the optimal therapeutic management for the patient.

Antioxidant-based topical formulations influence on the inflammatory response of Japanese skin: A clinical study using non-invasive techniques

Cutaneous irritants exposure induces an excess of ROS in the skin and can ensue an inflammatory response. Topical antioxidant-based formulations can help to counteract ROS generation. This study evaluated the influence of antioxidant-based topical formulations on the inflammatory response of skin, using a combination of in vivo real-time non-invasive techniques. Nine test areas were defined on each volar forearm of the 25 Japanese volunteers. Measurements were performed before and after treatment with 15μL of a 5% sodium dodecyl sulfate solution and 15μL of the same based formulation or the vehicle with 1% of the antioxidants. Volunteers without antioxidant treatment showed more pronounced erythematous areas. Transepidermal water loss of areas treated with green tea polyphenol (GTP)-based formulation showed fully recovered skin. Skin barrier damage caused by repeated applications of SDS showed characteristic alterations, detectable by in vivo confocal microscopy such as desquamation, spongiosis and inflammatory infiltrates. The majority of confocal microscopy inflammation signs were found in skin without treatment followed by the vehicle. Ascorbyl tetraisopalmitate, Coenzyme Q₁₀, GTP- and Resveratrol-based formulations reduced the anti-inflammatory cytokines release and attenuated inflammatory signs. The combination of techniques provides results that highlight the importance of antioxidant-based formulations for rapid skin recovery.

Monitoring treatment response in psoriasis: current perspectives on the clinical utility of reflectance confocal microscopy

Reflectance confocal microscopy (RCM) evaluation of inflammatory skin diseases represents a relatively new technique that, during the past 5 years, has attracted increasing interest, with consequent progressive increment of publications in literature. The success of RCM is directly related to the high need for noninvasive techniques able to both reduce the number of skin biopsies and support clinical diagnosis and patient management. RCM helps to visualize microscopic descriptors of plaque psoriasis (PP) with good reproducibility between observers and a high grade of correspondence with histopathology. Several clinical tests are used for the therapeutic management of PP, but they are limited by subjective interpretation. Skin biopsy presents objective interpretation, but the procedure is invasive and not repeatable. RCM has been used not only for the evaluation of skin cancer or inflammatory skin diseases, but also for monitoring the efficacy of different treatments in PP. In this review, we present some examples of RCM applications in therapeutic psoriasis follow-up.