Dermatoscopy and Reflectance Confocal Microscopy Correlations in Nonmelanocytic Disorders

The role of in vivo reflectance confocal microscopy for the management of acne: A systematic review

Acne diagnosis, severity assessment and treatment follow-up rely primarily on clinical examination. In vivo reflectance confocal microscopy (RCM) provides non-invasively, real-time images of skin lesions with a level of detail close to histopathology. This systematic literature review aims to provide an overview of RCM utility in acne and a summary of specific features with clinical application that may increase objectivity in evaluating this condition. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting our results. We systematically searched three databases: PubMed, Clarivate and Google Scholar (January 2022). All included studies used RCM to investigate acne in human patients and reported the investigated skin area and type (acne lesions or clinically uninvolved skin), the substance used in the case of treatment. Our search identified 2184 records in the three databases investigated. After duplicate removal, 1608 records were screened, 35 were selected for full-text assessment, and 14 were included in this review. We used the QUADAS-2 tool to evaluate the risk of bias and applicability concerns. RCM was selected as the index test and clinical examination as the reference standard. The total number of patients from all studies was 291, with 216 acne patients and 60 healthy participants aged between 13 and 45 years. The 14 considered studies analysed 456 follicles from healthy participants, 1445 follicles from uninvolved skin in acne patients and 1472 acne lesions. Consistent RCM findings concerning follicles of acne patients reported across studies were increased follicular infundibulum size, thick, bright border, intrafollicular content and inflammation. Our analysis indicates that RCM is a promising tool for acne evaluation. Nevertheless, standardization, a unified terminology, consistent research methods and unitary reporting of RCM findings are necessary. PROSPERO registration number CRD42021266547.

Skin surface material for detecting human papillomavirus infection of skin warts

Warts, caused by human papillomavirus (HPV) infection, have various clinical presentations, making them difficult to differentiate from clavus, callus, and sometimes, squamous cell carcinoma. Although skin biopsies are the gold standard, a less-invasive method of examining these lesions is desired. Ninety patients with warts and related diseases, such as clavus and callus, were recruited to explore new differentiation methods using the surface of the warts. DNA was extracted from three types of specimens in each case: surface swab, shaved hyperkeratotic scale, and post-shaved surface swab. Total DNA was successfully extracted from these three specimens and was sufficient for subsequent HPV DNA detection. We analyzed samples for the HPV type and HPV viral load using polymerase chain reaction (PCR). Fifty-five cases were PCR-positive, and HPV1a, 2a, 4, 27, 57, and 65 were detected. The amount of HPV1a DNA produced was significantly greater than that of other HPV types. Regarding the correlation between the clinical diagnosis and HPV detection, the positive agreement rate was 90.9%, the negative agreement rate was 40.0%, and the overall agreement rate was 71.1%. Ten of the 21 cases clinically diagnosed as plantar warts were PCR-negative, especially in elderly patients. This suggests that it is difficult to distinguish plantar warts from clavus and callus in clinical practice. Although the amount of HPV DNA in the removed keratinization scale was highest for all HPV types, HPV detection by swabbing before and after shaving is also useful for follow-up as well as for differential diagnosis.

Dermatoscopy of Cutaneous Lichen Planus - Attempt to Translate Metaphoric Terminology Into Descriptive Terminology

INTRODUCTION

Dermatoscopy is gaining appreciation in assisting the diagnosis of inflammatory dermatoses (inflammoscopy). Lichen planus (LP) is a common inflammatory skin disease with characteristic dermatoscopic features. Over the last few years, numerous articles were published on the dermatoscopy of LP and a high number of terms have been used to describe the dermatoscopic features of this disease.

OBJECTIVES

The objective of this study was to review the literature on the dermatoscopy of LP and to re-evaluate the published descriptions in the light of the 2019 expert consensus on the terminology of dermatoscopy for non-neoplastic skin diseases.

METHODS

We searched the PubMed database using the keywords 'lichen planus and dermatoscopy', 'lichen planus and dermoscopy', 'lichen planus and epiluminescence microscopy', and 'lichen planus and inflammoscopy'.

RESULTS

Of 408 articles retrieved, we selected 67 articles for full-text review, and finally included 58 articles, mostly case reports or small case series, comprising 572 patients with LP. We identified 118 different terms or short descriptions that were used to characterize the dermatoscopy of LP and redescribed them according to International Dermoscopy Society consensus paper. Frequently, authors applied various terms or descriptions to variants of the same feature. Although reported under different designations, Wickham striae were the most consistent dermatoscopic feature of LP. Other characteristics of LP, such as vascular patterns, pigmented structures and follicular findings were less consistent or depended on skin type, anatomic site, disease stage and applied treatment.

CONCLUSIONS

While Wickham striae are the single most important clue for the diagnosis, other dermatoscopic characteristics of LP are less consistent. Based on the descriptions published in the literature we established a dictionary of useful terms for the description of LP that is consistent with the terminology suggested by the recent consensus conference.

Diagnostic aid to subepidermal calcified nodule with dermoscopy and reflectance confocal microscopy: a case report

BACKGROUND

Subepidermal calcified nodule (SCN) is a type of calcinosis cutis that usually occurs in children. The lesions in the SCN resemble those of other skin diseases, such as pilomatrixoma, molluscum contagiosum, and juvenile xanthogranuloma, leading to a high rate of misdiagnoses. Noninvasive in vivo imaging techniques, represented by dermoscopy and reflectance confocal microscopy (RCM), have dramatically accelerated skin cancer research over the past decade, and their applications have greatly expanded into other skin disorders. However, the features of an SCN in dermoscopy and RCM have yet to be reported previously. Combining these novel approaches with conventional histopathological examinations is a promising method for increasing diagnostic accuracy.

CASE PRESENTATION

We report on a case of SCN of the eyelid diagnosed with the aid of dermoscopy and RCM. A 14-year-old male patient who presented with a painless yellowish-white papule on his left upper eyelid was previously diagnosed with a common wart. Unfortunately, treatment with recombinant human interferon gel was not effective. To achieve a correct diagnosis, dermoscopy and RCM were performed. The former showed closely grouped multiple yellowish-white clods surrounded by linear vessels, and the latter exhibited hyperrefractile material nests at the dermal-epidermal junction level. The alternative diagnoses were, therefore, excluded because of in vivo characterizations. Subsequent surgical excision, histological examination, and von Kossa staining were performed. Pathology showed hyperkeratosis of the epidermis, a downward-directed basal-layer expansion, and small amorphous basophilic deposits scattered throughout the papillary dermis. The von Kossa staining confirmed calcium deposits in the lesion. An SCN was then diagnosed. During the 6-month follow-up, no relapse was observed.

CONCLUSIONS

Patients with SCN could benefit from dermoscopy and RCM, which help achieve an accurate diagnosis. Clinicians should consider the possibility of an SCN for an adolescent patient with painless yellowish-white papules.

Dermoscopy, Reflectance Confocal Microscopy and Optical Coherence Tomography Features of Acne: A Systematic Review

Noninvasive imaging techniques have recently outlined precise microscopic features of acne elementary lesions and accurate quantifications for disease severity staging and therapeutical efficacy follow-up. The aim of this review is to systematically describe current applications of dermoscopy, reflectance confocal microscopy (RCM), and optical coherence tomography (OCT) in acne vulgaris assessment and management. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We included studies conducted on human subjects with elementary lesions of acne vulgaris, reporting assessment of the lesions with dermoscopy, RCM, and/or OCT. At present there are few large studies regarding acne and noninvasive imaging techniques, representing the main limitation of this review. Clinical examination represents the first line in acne diagnosis and treatment. However, dermoscopy, RCM, and OCT are further tools that can improve acne classification, monitoring of treatment, and pathophysiologic characterization. In the near future, dermoscopy, RCM, and OCT could become routinely used for the evaluation of acne vulgaris to provide a deeper knowledge of the disease and to guide the clinician in the prescription of tailored treatment protocols based on each patient’s characteristics.

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.

Line-field confocal optical coherence tomography of xanthogranuloma: Correlation with vertical and horizontal histopathology

Line‐field confocal optical coherence tomography (LC‐OCT) is a new noninvasive technique for a real‐time, vertical, and horizontal imaging of the skin at cellular resolution. A 47‐year‐old female presented with a 6‐month history of an asymptomatic yellowish papule. LC‐OCT evaluation was able to show the diagnostic microscopic features of xanthogranuloma and showed an excellent correlation with vertical and horizontal histopathological sections by revealing enlarged dermal papillae containing multiple, bright roundish giant cells, corresponding to foamy histiocytes, and giant cells characterized by a dark center surrounded by a highly hyper‐refractile peripheral ring, corresponding to Touton cells. LC‐OCT may represent a valid, noninvasive alternative to histopathological examination in clinically atypical cases of xanthogranuloma.

Evaluation of capillary density in psoriasis: An intrapatient study and literature review

Background

Dilated and tortuous vessels within elongated dermal papillae represent a histopathological clue of psoriasis. However, the number of dilated capillaries (capillary density) in psoriasis remains undefined as the results from the available studies differ significantly.

Objectives

To evaluate the capillary density in psoriasis using dermoscopy and horizontal histopathological sections (HHS), two techniques that share the horizontal view of the skin, and to compare the results with the existing data.

Methods

Twenty adult patients with stable plaque psoriasis were enrolled and, in each patient, a target area of the examined plaque, previously engraved by gently rotating a 5-mm biopsy punch device, underwent dermoscopy and biopsy for HHS. In all examined fields, capillary density was evaluated in a centered 4-mm diameter area, counting the number of red dots at dermoscopy and of dermal papillae at HHS.

Results

A total of 20 target lesions located on the trunk, arms and tights were evaluated. The mean capillary density resulting from dermoscopy was 43.02±6.60/mm 2 whereas that from HHS was 50.30±9.05/mm 2. These data showed a statistically significant difference (p = 0.006), with a strong correlation at Pearson’s test (r = 0.88).

Conclusions

Our results when compared with those from the existing literature showed some differences. The peculiarity of our work is represented by the precise measurement and correlation of the capillary density using two different methods, as the preliminary skin engraving allowed a perfect match between the area undergoing dermoscopy and that of skin sampling for HHS. Compared to dermoscopy in which deep-located vessels might have gone undetected, HHS seems to reflect more precisely and reliably the real capillary density showing an average of 50 capillaries/mm 2 that in a common 5x5 cm psoriatic patch corresponds to an average of 125.000 capillaries. These results highlight the extraordinary potential of psoriatic skin to develop such a complex and intricate vascular network.

Correlation Between In Vivo Reflectance Confocal Microscopy and Horizontal Histopathology in Skin Cancer: A Review

In dermatopathological daily practice, vertical histopathology sections are classically used to analyze skin biopsies. Conversely, horizontal histopathological sections are currently used for the diagnosis of some types of alopecia. In the last years the morphological findings obtained by horizontal histopathology have been correlated to those obtained by in vivo reflectance confocal microscopy which provides the same “point of view” of the skin. This review paper emphasizes the strong matching and correlation between reflectance confocal microscopy images and horizontal histopathology in cutaneous neoplasms, further demonstrating the strong reliability of this innovative, non-invasive technique in the management of skin tumors.

A Clinical Perspective on the Automated Analysis of Reflectance Confocal Microscopy in Dermatology

BACKGROUND AND OBJECTIVES

Non-invasive optical imaging has the potential to provide a diagnosis without the need for biopsy. One such technology is reflectance confocal microscopy (RCM), which uses low power, near-infrared laser light to enable real-time in vivo visualization of superficial human skin from the epidermis down to the papillary dermis. Although RCM has great potential as a diagnostic tool, there is a need for the development of reliable image analysis programs, as acquired grayscale images can be difficult and time-consuming to visually assess. The purpose of this review is to provide a clinical perspective on the current state of artificial intelligence (AI) for the analysis and diagnostic utility of RCM imaging.

STUDY DESIGN/MATERIALS AND METHODS

A systematic PubMed search was conducted with additional relevant literature obtained from reference lists.

RESULTS

Algorithms used for skin stratification, classification of pigmented lesions, and the quantification of photoaging were reviewed. Image segmentation, statistical methods, and machine learning techniques are among the most common methods used to analyze RCM image stacks. The poor visual contrast within RCM images and difficulty navigating image stacks were mediated by machine learning algorithms, which allowed the identification of specific skin layers.

CONCLUSIONS

AI analysis of RCM images has the potential to increase the clinical utility of this emerging technology. A number of different techniques have been utilized but further refinements are necessary to allow consistent accurate assessments for diagnosis. The automated detection of skin cancers requires more development, but future applications are truly boundless, and it is compelling to envision the role that AI will have in the practice of dermatology. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Diagnostic Accuracy of Dermoscopy for Scabies

The diagnostic accuracy of dermoscopy (DS) for scabies, a highly contagious parasitic disease, remains disputed. This study aimed to assess the diagnostic accuracy of DS in scabies, analyze the factors influencing DS, and explore its role in post-treatment evaluation. Patients with suspected scabies were randomly divided into 2 groups: 71 patients in the skin scraping (SS) group and 73 patients in the DS group. The diagnostic efficiencies of SS and DS in these groups were calculated. We also analyzed the influence of body part and investigator competence on the accuracy of DS. Then 16 body parts with typical signs of scabies were monitored by DS 2 and 4 day after sulfur ointment treatment. The sensitivity and specificity of DS were 98.3% and 88.5%, respectively. Hands, arms, and the abdomen had higher positivity rates than other body parts (P<0.001). The accuracy of dermatologists’ interpretations of images negative for scabies in the intermediate- and high-level groups was higher than that in the low-level group (P<0.001). At follow-up, the mites were still visible on 43.8% to 62.5% of the skin lesions 2 and 4 day after sulfur ointment treatment. These results showed that DS could significantly increase the accuracy of diagnosing scabies owing to its high sensitivity and specificity. Therefore, it may be useful for monitoring clinical responses to anti-parasitic treatment.

The combined role of clinical, reflectance confocal microscopy and dermoscopy applied to chronic discoid cutaneous lupus and subacutus lupus erythematosus: A case series and literature review

Main subtypes of cutaneous lupus erythematosus are represented by acute, subacute cutaneous, intermittent and chronic cutaneous lupus erythematosus. Discoid lupus erythematosus represents the most common phenotype of chronic cutaneous lupus erythematosus. The spectrum of clinical manifestations mirrors that of several and distinct histopathological features. Such variability among different CLE subtypes is also observed at dermoscopy. Dermoscopy is nowadays considered an additional valuable method for skin lesions assessment in general dermatology, following and completing the well-known clinical diagnostic steps, such as medical history and clinical examination. In vivo reflectance confocal microscopy (RCM) is a non-invasive imaging tool able to assess the epidermis and upper dermis producing high resolution (horizontal ∼1.25 μm, vertical ∼5 μm), en face tissue sections used for melanocytic and inflammatory evaluation. In this study, we reported dermoscopic and RCM features about 9 patients affected by subacute and chronic lupus erythematosus retrospectively analyzed.

Dermoscopy of genital diseases: a review

The male and female external genital regions are anatomical areas in which various types of skin disorders may occur. Although most of these conditions can be diagnosed by means of clinical examination and an accurate medical history, in most cases further investigations with time-consuming and/or invasive procedures are needed in order to reach the correct diagnosis. Dermoscopy, as a modern non-invasive tool, is able to better diagnose pigmented and non-pigmented skin tumours along with various inflammatory and infectious skin and appendage disorders. The aim of this paper was to provide a review of the use of dermoscopy in genital disorders based on published data and to include personal experience gained from real life, focusing on any possible gender difference and whether disease mucosal/semimucosal dermoscopy features may differ from those observed on the skin. In conclusion, genital dermoscopy should always be considered during clinical inspection in order to enhance the diagnosis or to rule out those conditions that may look similar but that show a different dermoscopy pattern, thus narrowing down the differential diagnoses and avoiding unnecessary invasive investigations.

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.

Inverse Psoriasis: From Diagnosis to Current Treatment Options

Inverse psoriasis represents a clinical variant of psoriasis that is sometimes difficult to diagnose due to its clinical similarity with other skin disorders involving the folds, mainly including mechanical intertrigo, fungal and bacterial infections, contact dermatitis, seborrheic dermatitis, and lichen planus. Dermoscopy represents a useful tool for an enhanced non-invasive diagnosis. The treatment of inverse psoriasis may be challenging and include topical corticosteroids, topical calcineurin inhibitors, vitamin D analogs, traditional oral systemic therapies such as cyclosporine and methotrexate, and biologic therapies.

Non-invasive Approaches for the Diagnosis of Autoimmune/Autoinflammatory Skin Diseases-A Focus on Psoriasis and Lupus erythematosus

The traditional diagnostic gold standard for inflammatory skin lesions of unclear etiology is dermato-histopathology. As this approach requires an invasive skin biopsy, biopsy processing and analysis by specialized histologists, it is a resource intensive approach requiring trained healthcare professionals. In many health care settings access to this diagnostic approach can be difficult and outside emergency cases will usually take several weeks. This scenario leads to delayed or inappropriate treatment given to patients. With dramatically increased sensitivity of a range of analysis systems including mass spectrometry, high sensitivity, multiplex ELISA based systems and PCR approaches we are now able to "measure" samples with unprecedented sensitivity and accuracy. Other important developments include the long-term monitoring of parameters using microneedle approaches and the improvement in imaging systems such as optical coherence tomography. In this review we will focus on recent achievements regarding measurements from non-invasive sampling, in particular from plucked hair and skin tape-strips which seem well suited for the diagnosis of lupus erythematosus and psoriatic inflammation, respectively. While these approaches will not replace clinical observation-they can contribute to improved subgroup diagnosis, stratified therapeutic approaches and have great potential for providing molecular and mechanistic insight in to inflammatory skin diseases.

Alternative uses of dermoscopy in daily clinical practice: An update

Dermoscopy is a noninvasive diagnostic tool that is currently being used for neoplastic skin lesions, several inflammatory and infectious diseases, and skin appendage disorders. As the clinical applications of dermoscopy beyond pigmented lesions are constantly increasing, the aim of this article is to provide an update on this topic. This comprehensive review substantiates how several diseases may show peculiar dermoscopy features so as to enhance the diagnosis and avoid (in selected cases) unnecessary histologic confirmation. In other cases, dermoscopy features may be shared with other conditions, with the advantage of narrowing down the differential diagnosis by ruling out those dermatoses with similar clinical aspect but different dermoscopic presentation.