Identification of ex-vivo confocal laser scanning microscopic features of melanocytic lesions and their histological correlates

Ex vivo confocal microscopy features of common benign lesions that mimic non-melanoma skin cancers: Towards clinical integration

Ex vivo confocal microscope (EVCM) rapidly images freshly excised tissue at a histopathological resolution. EVCM features of keratinocyte skin cancers are well-established, but those of benign clinical mimickers remain scarce. We describe EVCM features of common benign lesions and compare them with their malignant differentials. EVCM was used to image 14 benign and 3 cancer tissues. We compared EVCM features of benign lesions with corresponding histopathology and with those of keratinocyte cancers. Key features of benign lesions were identified and differentiated from malignant lesions. Elastin and fat appeared prominent in EVCM; while koilocytes and melanin were difficult to identify. Visualization of entire epidermis was challenging due to difficulty of tissue flattening during imaging. Benign lesions can be differentiated from keratinocyte cancers with EVCM. Using EVCM, a rapid, bedside diagnosis and management of skin neoplasms is possible, especially in a remote location without a histopathology lab.

Role of VivaScope 2500 ex vivo confocal microscopy in skin pathology: Advantages, limitations, and future prospects

BACKGROUND

Vivascope 2500 ex vivo confocal microscopy (EVCM) is an emerging optical imaging device that allows nuclear level resolution of freshly excised tissues. EVCM provides, rapid real-time pathological examination in many subspecialties of pathology including skin, prostate, breast, liver, etc. In contrast to traditional time-consuming frozen sectioning and histological analysis.

AIMS

To evaluate the current state of EVCM utilization.

MATERIALS AND METHODS

This study highlights the advantages, limitations, and prospects of EVCM in skin pathology.

RESULTS

Our findings demonstrate that EVCM is a promising adjunctive tool to assess margins in Mohs surgery and to provide rapid, accurate diagnosis of cutaneous tumors, infectious and inflammatory diseases.

CONCLUSION

EVCM is a revolutionary device that can be used as an adjunct to paraffin-fixed, hematoxylin and eosin-stained slides and frozen sectioning. Additional refinements are required before EVCM can be used as an alternative to frozen sectioning or traditional tissue processing.

A Feasibility Study for Immediate Histological Assessment of Various Skin Biopsies Using Ex Vivo Confocal Laser Scanning Microscopy

BACKGROUND

Digitally stained ex vivo confocal laser scanning microscopy (CLSM) scans are a possible alternative to formalin-fixed and paraffin-embedded (FFPE) and hematoxylin-eosin (H&E) stained slides. This study explores the diagnostic accuracy of digitally-stained CLSM scans in comparison to H&E-stained slides in various dermatologic diseases in a real-life setting.

METHODS

Samples of patients out of one selected dermatologic office were primarily scanned via CLSM; a diagnosis was made afterwards using FFPE- and H&E-stained slides by two experienced dermatopathologists. Primary outcomes were sensitivity and specificity of diagnosis in digitally stained CLSM scans in three separate diagnostic groups.

RESULTS

CLSM evaluation of epithelial tumors (n = 132) demonstrated a sensitivity of 64.3%/83.9% and a specificity of 84.2%/71.1%. Diagnosis of melanocytic tumors (n = 86) showed a sensitivity of 19.1%/85.1% and a specificity of 96.3%/66.7%. In the diagnosis of other tumors/cysts and inflammatory dermatoses (n = 42), a sensitivity of 96.4%/96.8% and a specificity of 57.1%/45.5% was reached.

CONCLUSIONS

This study shows the possibilities and limitations of a broad use of CLSM. Because of a partly low diagnostic accuracy, such an application does not seem to be recommendable at present for every indication.

Ex vivo confocal laser scanning microscopy: A diagnostic technique for easy real-time evaluation of benign and malignant skin tumours

Ex vivo confocal laser scanning microscopy (ex vivo CLSM) is a novel diagnostic tool for a quick bedside evaluation of freshly excised tissue, comparable to histology. We aimed to assess the sensitivity and specificity of ex vivo CLSM in detecting malignant features, to validate its reliability in identifying various skin tumours based on a combination of confocal features and to evaluate the digital staining mode (DS). One-hundred twenty freshly excised skin samples from 91 patients were evaluated. Each lesion was screened for the presence of 23 predefined confocal criteria with ex vivo CLSM, followed by a histopathological examination. The diagnostic agreement between ex vivo CLSM and histology was 89.2%. The diagnostic accuracy of ex vivo CLSM in detecting malignancy reached a sensitivity of 98% and a specificity of 76%. Ex vivo CLSM enabled a rapid identification of the most common skin tumours, the tumour dignity and cytological features. The DS demonstrated a close resemblance to conventional histopathology.

Line-Field Confocal Optical Coherence Tomography: A New Tool for the Differentiation between Nevi and Melanomas?

Until now, the clinical differentiation between a nevus and a melanoma is still challenging in some cases. Line-field confocal optical coherence tomography (LC-OCT) is a new tool with the aim to change that. The aim of the study was to evaluate LC-OCT for the discrimination between nevi and melanomas. A total of 84 melanocytic lesions were examined with LC-OCT and 36 were also imaged with RCM. The observers recorded the diagnoses, and the presence or absence of the 18 most common imaging parameters for melanocytic lesions, nevi, and melanomas in the LC-OCT images. Their confidence in diagnosis and the image quality of LC-OCT and RCM were evaluated. The most useful criteria, the sensitivity and specificity of LC-OCT vs. RCM vs. histology, to differentiate a (dysplastic) nevus from a melanoma were analyzed. Good image quality correlated with better diagnostic performance (Spearman correlation: 0.4). LC-OCT had a 93% sensitivity and 100% specificity compared to RCM (93% sensitivity, 95% specificity) for diagnosing a melanoma (vs. all types of nevi). No difference in performance between RCM and LC-OCT was observed (McNemar's p value = 1). Both devices falsely diagnosed dysplastic nevi as non-dysplastic (43% sensitivity for dysplastic nevus diagnosis). The most significant criteria for diagnosing a melanoma with LC-OCT were irregular honeycombed patterns (92% occurrence rate; 31.7 odds ratio (OR)), the presence of pagetoid spread (89% occurrence rate; 23.6 OR) and the absence of dermal nests (23% occurrence rate, 0.02 OR). In conclusion LC-OCT is useful for the discrimination between melanomas and nevi.

Progress in the application of reflectance confocal microscopy in dermatology

Reflectance confocal microscopy (RCM) is abbreviated as skin three-dimensional computed tomography, which can help clearly observe the structure of the epidermis and superficial dermis. It is a non-invasive skin disease examination method and provides fast access to real-time, dynamic skin micro-anatomical images. Therefore, RCM is widely used in the clinical diagnosis of skin diseases. For example, the RCM features of vitiligo are as follows: pigment loss or partial pigment loss in the lesion area, loss of the basal layer pigment ring. The RCM findings of Riehl melanosis are as follows: basal cell liquefaction and degeneration. The RCM results for verruca plana show: the Rose-like structure. The characteristics of psoriasis under RCM include: hyperkeratosis, parakeratosis, thickening of the spinous layer, capillary dilatation and hyperaemia, peripheral inflammatory cell infiltration. Epidermal brain-like structure was observed under RCM of seborrheic keratosis. With RCM, image acquisition and preservation of the skin is convenient, and the technique is convenient for comparing the development of lesions during long-term follow-up observation. Therefore, it helps to understand disease development in real time and dynamically and can be used to evaluate the curative effect. In this article, we briefly review the technical principles, diagnostic criteria for RCM application and RCM-related research progress in the diagnosis of pigmentary diseases, inflammatory diseases, skin tumours, and other common skin diseases.

Machine Learning Based Prediction of Squamous Cell Carcinoma in Ex Vivo Confocal Laser Scanning Microscopy

Image classification with convolutional neural networks (CNN) offers an unprecedented opportunity to medical imaging. Regulatory agencies in the USA and Europe have already cleared numerous deep learning/machine learning based medical devices and algorithms. While the field of radiology is on the forefront of artificial intelligence (AI) revolution, conventional pathology, which commonly relies on examination of tissue samples on a glass slide, is falling behind in leveraging this technology. On the other hand, ex vivo confocal laser scanning microscopy (ex vivo CLSM), owing to its digital workflow features, has a high potential to benefit from integrating AI tools into the assessment and decision-making process. Aim of this work was to explore a preliminary application of CNN in digitally stained ex vivo CLSM images of cutaneous squamous cell carcinoma (cSCC) for automated detection of tumor tissue. Thirty-four freshly excised tissue samples were prospectively collected and examined immediately after resection. After the histologically confirmed ex vivo CLSM diagnosis, the tumor tissue was annotated for segmentation by experts, in order to train the MobileNet CNN. The model was then trained and evaluated using cross validation. The overall sensitivity and specificity of the deep neural network for detecting cSCC and tumor free areas on ex vivo CLSM slides compared to expert evaluation were 0.76 and 0.91, respectively. The area under the ROC curve was equal to 0.90 and the area under the precision-recall curve was 0.85. The results demonstrate a high potential of deep learning models to detect cSCC regions on digitally stained ex vivo CLSM slides and to distinguish them from tumor-free skin.

[Ex vivo confocal laser scanning microscopy for melanocytic lesions and autoimmune diseases]

BACKGROUND

Ex vivo confocal laser scanning microscopy (CLSM) enables bedside histology and offers the surgeon a direct intraoperative tissue examination.

OBJECTIVES

To determine whether this innovative, ultra-fast diagnostic tool can be expanded beyond nonmelanoma skin cancer, particularly basal cell carcinoma, to other indications including melanocytic lesions and autoimmune diseases.

MATERIALS AND METHODS

Review of literature and summary of the current knowledge and experience of the use of ex vivo CLSM in melanocytic lesions and in autoimmune diseases.

RESULTS

Up to date experience of the use of ex vivo CLSM in melanocytic lesions and in autoimmune diseases is limited but promising. Current knowledge on melanocytic lesions in ex vivo CLSM and their examples together with classic ex vivo CLSM features are presented. Previous results on the use of ex vivo CLSM in autoimmune dermatoses are presented, and future application possibilities of ex vivo CLSM are discussed.

CONCLUSIONS

The method is particularly suitable for the rapid examination of basal cell carcinomas during Mohs surgery but could also be used in the future for the intraoperative examination of melanocytic and autoimmune skin lesions.

Ex-vivo fluorescence confocal microscopy with digital staining for characterizing basal cell carcinoma on frozen sections: A comparison with histology

Ex-vivo fluorescence confocal microscopy (FCM) has been used on fresh tissue, but there is little experience on frozen sections. We evaluated the applicability of FCM on frozen sections of basal cell carcinomas (BCCs), stained with acridine orange and digitally colored to simulate hematoxylin and eosin (H&E) dyes. We compared our diagnostic accuracy in detecting and subtyping BCCs with FCM to our gold standard (H&E stained frozen sections used in 3D horizontal micrographic surgery). Fourty-six primary BCCs were analyzed for free margins as well as histological subtype with all FCM modes and conventional H&E staining. Adnexa, artifacts and diagnostic confidence were evaluated. Free margins were identified with a sensitivity and specificity of 92% and 91%. Concordance for tumor subtype was 88%. FCM may be used on both fresh tissue and frozen samples, although with reduced performance and different artifacts. The device is useful for the intraoperative diagnosis, subtyping and margin-mapping of BCCs.

Feasibility study for ex vivo fluorescence confocal microscopy (FCM) on diagnostic prostate biopsies

Background

Fluorescence confocal microscopy (FCM) is a novel micro-imaging technique providing optical sections of examined tissue. The method has been well established for the diagnosis of tumours in dermatological specimens. Preliminary results found good feasibility when this technique was used to examine prostate cancer (PCa) specimens.

Methods

We report on the application of FCM in magnet resonance imaging (MRI)-fused prostate biopsies (10 patients, total number of biopsy specimens: n=121) and compare the results to conventional histology.

Results

Specific structures of the prostatic tissue were very well represented in the FCM images comparable to conventional histology. Prostate carcinoma was diagnosed with good sensitivity (79/68%) and high specificity (100%) by two pathologists with substantial/almost perfect levels of agreement with the results of conventional histology (kappa 0.79/0.86). Depending on the quality of the scans, malignant lesions of 1.8 mm and more in diameter were reliably diagnosed. Smaller lesions were rated as suspect for malignancy, but could not be consistently differentiated from reactive changes. Optimal image qualities were achieved in focus depths of up to 50 µm, whereas deeper scans led to insufficient representation of cytological features. Pre-treatment with acridine orange (AO) did not alter immunoreactivity of the tissue or its feasibility for fluorescence in situ hybridization (FISH) analyses and adequate amounts of DNA could be extracted for further polymerase chain reaction (PCR)-based examinations.

Conclusions

FCM seems to be a promising tool for the timely diagnosis in cases of PCa in patients requiring therapy. In particular, this technique is a material-sparing method that conserves the biopsies as unfixed material for further analysis such as molecular tumour companion diagnosis.

New-generation diagnostics in inflammatory skin diseases: Immunofluorescence and histopathological assessment using ex vivo confocal laser scanning microscopy in cutaneous lupus erythematosus

Ex vivo confocal laser scanning microscopy (CLSM) offers real-time examination of excised tissue in reflectance, fluorescence and digital haematoxylin-eosin (H&E)-like staining modes enabling application of fluorescent-labelled antibodies. We aimed to assess the diagnostic performance of ex vivo CLSM in identifying histopathological features and lupus band test in cutaneous lupus erythematosus (CLE) with comparison to conventional histopathology and direct immunofluorescence (DIF). A total of 72 sections of 18 CLE patients were stained with acridine orange (AO), anti-IgG, anti-IgM and anti-IgA; 21 control samples were stained with AO. Subsequently, ex vivo CLSM examination of all samples was performed in reflectance, fluorescence and digital H&E-like staining modes. Superficial and deep perivascular inflammatory infiltration (94.4%), interface dermatitis (88.9%), spongiosis (83.3%) and vacuolar degeneration (77.7%) were the most common features detected with ex vivo CLSM. Kappa test revealed a level of agreement ranging within "perfect" to "good" between ex vivo CLSM and conventional histopathology. ROC analysis showed that the combination of perivascular infiltration, interface dermatitis and spongiosis detected by ex vivo CLSM has the potential to distinguish between CLE and controls. Basement membrane immunoreactivity with IgG, IgM and IgA was identified in 88.8% (n = 15), 55.5% (n = 10) and 55.5% (n = 10) of the CLE samples using ex vivo CLSM, respectively, whereas DIF showed IgG, IgM and IgA positivity in 94.4% (n = 17), 100% (n = 18) and 88.9% (n = 16) of patients, respectively. In conclusion, ex vivo CLSM enables simultaneous histopathological and immunofluorescence examination in CLE showing a high agreement with conventional histopathology, albeit with a lower performance than conventional DIF.

Immunofluorescence and histopathological assessment using ex vivo confocal laser scanning microscopy in lichen planus

Ex vivo confocal laser scanning microscopy (CLSM) provides rapid, high-resolution imaging, fluorescence detection and digital haematoxylin-eosin (H&E)-like staining. We aimed to assess the performance of ex vivo CLSM in identifying histomorphology and immunoreactivity in lichen planus (LP) and comparing its accuracy with conventional histopathology and direct immunofluorescence (DIF). Thirty-three sections of 17 LP patients stained with acridine orange (AO) and FITC-labelled anti-fibrinogen antibody and 21 control samples stained with AO were examined using ex vivo CLSM. Ex vivo CLSM was in perfect agreement with conventional histopathology in identifying interface dermatitis, vacuolar degeneration and band-like infiltration. ROC analysis showed that the presence of vacuolar degeneration, interface dermatitis and band-like infiltration was useful to distinguish LP sections from controls (p < .0001). The detection rates of fibrinogen deposition using DIF and in conclusion ex vivo CLSM were 93.8% and 62.5%, respectively. ex vivo CLSM enables histopathological and immunofluorescence examination in LP with the advantage of digital H&E-like staining.

Ex vivo Confocal Laser Scanning Microscopy: A Potential New Diagnostic Imaging Tool in Onychomycosis Comparable With Gold Standard Techniques

Ex vivo confocal laser scanning microscopy (CLSM) is an innovative imaging tool that enables real-time examination of specimens and may be used in evaluating fungal infections. We aimed to assess the applicability of ex vivo CLSM in the diagnosis of onychomycosis by comparing results to those obtained by histopathology, potassium hydroxide (KOH) examination, and fungal culture. In this prospective study, 57 patients with the clinical diagnosis of distal nail fungal infection were examined and compared using all four of the above-mentioned diagnostic tools in terms of sensitivity, positive and negative predictive value. Ex vivo CLSM showed the highest sensitivity, followed by KOH examination, histopathology and fungal culture. Regarding positive and negative predictive values, ex vivo CLSM was superior and showed even higher sensitivity than the combined gold standard comprised of KOH examination, fungal culture or histopathology.

In vivo and ex vivo confocal microscopy for the evaluation of surgical margins of melanoma

We report the first series of melanomas (MMs) where the surgical margins were evaluated both by ex vivo confocal microscopy (EVCM) and in vivo reflectance confocal microscopy (RCM). We evaluated the surgical margins of 42 cutaneous MMs of lentigo maligna/lentigo maligna melanoma type and 2 mucosal MMs with EVCM. Cutaneous MMs also underwent RCM mapping. Imaging results were compared with histopathology. The rate of correct identification of the tumor margins (invaded or not invaded) was 97.6% for RCM (evaluations of cutaneous MMs) and 95.5% for EVCM (evaluations of both cutaneous and mucosal MMs). Our study showed that the MM extension is visible under EVCM and that the combination of in vivo RCM and EVCM can be a new strategy for the evaluation of surgical margins of MMs.

Ex vivo confocal microscopy: revolution in fast pathology in dermatology

Confocal microscopy with in vivo and ex vivo modalities has been used in the evaluation of skin cancer and other dermatological disorders. Recent developments in ex vivo confocal microscopy allow for faster pathology assessment with greater accuracy by the visualization of cellular and architectural details, similarly to standard pathology, in either paraffin-embedded or frozen samples. They include the possibility of multimodal confocal microscopy using different lasers and fusion images. New staining protocols including immunostaining, with no damage to conventional histopathology preparation, have been recently described in melanocytic tumours and inflammatory skin diseases. Digital staining with haematoxylin and eosin is also incorporated in the new devices. In this review the applications of ex vivo confocal microscopy will be presented with the description of the technique and the technology, clinical evidence in dermatology and other fields, and further applications.

Evaluation of digital staining for ex vivo confocal laser scanning microscopy

BACKGROUND

Ex vivo confocal laser scanning microscopy (CLSM) is a novel diagnostic tool for the fast examination of native tissue. However, CLSM produces black/white/green images, depending on the refraction indices of the tissue structures, complemented by nuclear fluorescence staining, which the vast majority of Mohs surgeons and dermatopathologists are not trained to interpret. Digital staining is applicable to ex vivo CLSM investigations to simulate the images of conventional slides stained with haematoxylin and eosin (H&E).

OBJECTIVES

The aim of our study was to evaluate in detail the appearance of human skin structures using digitally stained ex vivo CLSM images and compare the results to that of conventional H&E slides of the same specimen.

METHODS

After providing informed consent, 26 patients donated their Burow's triangles (healthy skin) that resulted from plastic reconstruction after the R0 excision of skin tumours. After being investigated by ex vivo CLSM, including automated digital staining (VivaScope 2500M-4G, MAVIG GmbH), the specimens were fixed in formalin, embedded in paraffin and stained with H&E.

RESULTS

Almost all skin structures in the digitally stained ex vivo CLSM images morphologically resembled the structures in the histopathological images acquired from H&E slides. Due to the high refraction index of melanin, the hair shafts appeared bright pink, and the melanocytes and melanophages were poorly imaged, resulting in a strong pink appearance that vastly differed from the appearance of conventional H&E-stained histopathology.

CONCLUSIONS

Digital staining of ex vivo CLSM images is an easy and highly useful tool to facilitate the interpretation of black-field images generated by confocal laser scanning microscopy for dermatopathologists and Mohs surgeons who are familiar with H&E staining. Unlike the pigmented structures, the cutaneous and subcutaneous structures had excellent visualization with only minimal differences from their appearance on H&E slides.

Ex vivo confocal laser scanning microscopy: An innovative method for direct immunofluorescence of cutaneous vasculitis

Ex vivo confocal laser scanning microscopy (ex vivo CLSM) offers an innovative diagnostic approach through vertical scanning of skin samples with a resolution close to conventional histology. In addition, it enables fluorescence detection in tissues. We aimed to assess the applicability of ex vivo CLSM in the detection of vascular immune complexes in cutaneous vasculitis and to compare its diagnostic accuracy with direct immunofluorescence (DIF) microscopy. Eighty-two sections of 49 vasculitis patients with relevant DIF microscopy findings were examined using ex vivo CLSM following staining with fluorescent-labeled IgG, IgM, IgA, C3 and fibrinogen antibodies. DIF microscopy showed immunoreactivity of vessels with IgG, IgM, IgA, C3 and Fibrinogen in 2.0%, 49.9%, 12.2%, 59.2% and 44.9% of the patients, respectively. Ex vivo CLSM detected positive vessels with the same antibodies in 2.0%, 38.8%, 8.2%, 42.9% and 36.7% of the patients, respectively. The detection rate of positive superficial dermal vessels was significantly higher in DIF microscopy as compared to ex vivo CLSM (P < .05). Whereas, ex vivo CLSM identified positive deep dermal vessels more frequently compared to DIF microscopy. In conclusion, ex vivo CLSM could identify specific binding of the antibodies in vessels and showed a comparable performance to conventional DIF microscopy in diagnosing vasculitis.

The use of in vivo reflectance confocal microscopy for the diagnosis of melanoma

INTRODUCTION

The use of reflectance confocal microscopy (RCM) for imaging the skin non-invasively raised constantly during the last decade. One of the main field of application is skin cancer diagnosis, and in particular melanoma diagnosis. Several studies have investigated the diagnostic accuracy of RCM as compared to dermoscopic examination, and its value in enhancing early diagnosis of dermoscopic difficult melanomas. Areas covered: The purpose of this paper was to review the principles behind RCM image acquisition as well as to describe and discuss key RCM features of melanoma. Moreover, we conducted a literature search in order to highlight the current available evidence about RCM sensitivity and specificity in the diagnosis of melanoma. Expert commentary: During the last decade, we assisted at the increasing interest in non invasive imaging tools for the diagnosis of skin cancer. RCM is one of the most studied of a series of diagnostic methods that are emerging in the field of melanoma imaging. Most probably in the future, RCM will be more frequently available in tertiary referral centres, thus the knowledge of the pros and contra of the tool and its clinical applicability is of upmost importance in order to allow correct referrals with the final aim of improving diagnostic accuracy.

Diagnostic accuracy of a new ex vivo confocal laser scanning microscope compared to H&E-stained paraffin slides for micrographic surgery of basal cell carcinoma

BACKGROUND

For safe excision of malignant skin tumours, complete negative surgical margins are mandatory. The gold standard for analysis is frozen sections or paraffin-embedded haematoxylin and eosin (H&E)-stained slides. The production of H&E-stained slides is time-consuming (>20 h) while wounds remain unclosed. An upcoming method is confocal laser scanning microscopy (CLSM), a technique that scans unfixed fresh tissue rapidly.

OBJECTIVE

Evaluation of the process to generate and analyse CLSM images and assessment of the accuracy to detect basal cell carcinoma (BCC) tissue.

METHODS

Digital microscopic images were generated by the Histolog Scanner v1 from 544 fresh specimens of 148 BCCs that had been stained with a 0.01% proflavine solution. CLSM images were compared to the histological diagnoses of the corresponding H&E-stained slides.

RESULTS

A total of 525 images could be analysed. The sensitivity was 73% (95% CI = [65.27%; 80.47%]), and the specificity was 96% (95% CI = [93.40%; 97.60%]). Detection of BCCs in punch biopsies was certainly detected (sensitivity of 100%). The median total time to generate and evaluate a CLSM image was 5.17 min (maximum 20.17 min and minimum 2.05 min). The greatest challenge was flattening the specimen to assure complete representation of the surgical margins.

CONCLUSION

Confocal laser scanning microscopy is a time-saving and very effective alternative to classical paraffin-embedded or frozen sections. Patient treatment could be improved due to shorter hospital stays or faster outpatient therapy due to reduced intervals between surgical stages. Diagnostic accuracy of the microscope used still must be improved.

Ex vivo fluorescence confocal microscopy for intraoperative, real-time diagnosis of cutaneous inflammatory diseases: A preliminary study

Ex vivo fluorescence confocal microscopy (FCM) is an innovative imaging tool that can be used intraoperatively to obtain real-time images of untreated excised tissue with almost histologic resolution. As inflammatory diseases often share overlapping clinical features, histopathology evaluation is required for dubious cases, delaying definitive diagnoses, and therefore therapy. This study identifies key-features at ex vivo FCM for differential diagnoses of cutaneous inflammatory diseases, in particular, psoriasis, eczema, lichen planus and discoid lupus erythematosus. Retrospective ex vivo FCM and histological evaluations with relevant diagnoses were correlated with prospectively reported histopathologic diagnoses, to evaluate agreement and the level of expertise required for correct diagnoses. We demonstrated that ex vivo FCM enabled the distinction of the main inflammatory features in most cases, providing a substantial concordance to histopathologic diagnoses. Moreover, ex vivo FCM and histological evaluations reached a substantial agreement with histopathologic diagnoses both for all raters and for each operator. After a yet to be defined learning curve, these preliminary results suggest that dermatologists may be able to satisfactorily interpret ex vivo FCM images for correct real-time diagnoses. Despite some limitations mainly related to the equipment of FCM with a single objective lens, our study suggests that ex vivo FCM seems a promising tool in assisting diagnoses of cutaneous inflammatory lesions, with a level of accuracy quite close to that offered by histopathology. This is the first study to investigate ex vivo FCM application in cutaneous inflammatory lesions, and to evaluate the diagnostic capability of this technology.

Simple 3-criteria-based ex vivo confocal diagnosis of basal cell carcinoma

BACKGROUND

Fast and simple microscopic evaluation of basal cell carcinoma (BCC) together with its subtype determination would accelerate diagnostic and therapeutic procedures in dermatology including Mohs surgery.

OBJECTIVES

Assessing whether simplified 3-criteria-based ex vivo confocal microscopic (CM) examination can reliably predict BCC diagnosis and subtype. Analyzing interobserver agreement between expert and novice examiner.

METHODS

CM images of 235 skin samples from 150 patients were prospectively evaluated by 2 blinded examiners for the presence of 3 predefined BCC criteria namely presence of tumor mass, peripheral palisading and clefting.

RESULTS

Out of 235 skin samples 116 showed histological presence of BCC, confocally expert diagnosed a BCC in 110 and novice examiner in 107 samples. The overall sensitivity and specificity of detecting residual BCC was 96.6% and 98.7%, respectively. Confocally, examiners diagnosed correctly nodular BCC in 96.6%, respectively, 98.3%, superficial BCC in 96.8%, respectively, 93.5%, infiltrating BCC in 88.9%, respectively, 83.3% and other BCC subtype in 22.2%, respectively, 0% (expert and novice examiner, respectively).

CONCLUSION

Ex vivo CM allowed intraoperative examination of BCC based on only 3-criteria with high sensitivity and specificity, provided useful information on tumor subtype and showed that both experienced and non-experienced examiners may use this diagnostic approach with excellent results.

Ex vivo confocal microscopy: an emerging technique in dermatology

This review aims to give an overview of the current available applications of ex vivo confocal microscopy (EVCM) in dermatology. EVCM is a relatively new imaging technique that allows microscopic examination of freshly excised unfixed tissue. It enables a rapid examination of the skin sample directly in the surgery room and thus represents an alternative to the intraoperative micrographic control of the surgical margins of cutaneous tumors by standard microscopic examination on cryopreserved sections during Mohs surgery. Although this technique has mainly been developed for the margin’s control of basal cell carcinoma, many other skin tumors have been studied, including melanoma. Use of EVCM is continuing to evolve, and many possible applications are under investigation, such as the study of nails and hair diseases and the diagnosis of skin infections.

Ex vivo confocal microscopy features of cutaneous squamous cell carcinoma

BACKGROUND

Rapid microscopic evaluation of cutaneous squamous cell carcinoma (SCC), its grade of differentiation and level of invasiveness would enable better management of patients' therapy.

OBJECTIVES

Analyzing specific ex vivo confocal microscopy criteria whether they can predict diagnosis of invasive SCC vs carcinoma in situ and poorly differentiated or undifferentiated vs well and moderately differentiated SCC.

METHODS

Ex vivo confocal images of 102 SCCs in 57 patients were evaluated immediately after excision for the presence of predefined criteria based on confocal and histological knowledge.

RESULTS

In histopathological examination, 30 SCCs were in situ and 72 invasive. Of these, 29 invasive SCC tumors were well, 19 moderately, 15 poorly differentiated and 9 undifferentiated. χ² analysis demonstrated that presence of erosion/ulceration, plump bright or speckled cells in dermis, keratin pearls and peritumoral inflammatory infiltrate correlated with diagnosis of invasive SCC. Erosion/ulceration and peritumoral inflammatory infiltrate were observed more frequently in poorly differentiated or undifferentiated tumors. Plump bright or speckled cells in the dermis were observed less often in well-differentiated tumors. The presence of keratin pearls was associated with well or moderately differentiated tumors.

CONCLUSION

Ex vivo CLSM allowed rapid examination of SCC and provided useful information on invasiveness and grading of the tumor.

Immunofluorescence and confocal microscopy for ex-vivo diagnosis of melanocytic and non-melanocytic skin tumors: A pilot study

BACKGROUND

Ex-vivo confocal laser scanning microscopy (ex-vivo CLSM) offers rapid examination of freshly excised tissue. During the conventional examination immunohistochemistry enables to distinguish various cell types. The possibility of immunofluorescent techniques could enhance the accuracy of the diagnosis performed by ex-vivo CLSM.

METHODS

The tissue probes from various skin tumors were stained with FITC-labeled S-100A10, Melan-A and anti-Ber-EP4 antibodies before examination with ex-vivo CLSM in the fluorescence and reflectance modes. Results were compared to negative controls and conventional histopathology. The staining protocols were evaluated by establishing a scoring system according to the signal intensity found in ex-vivo CLSM.

RESULTS

S100 immunostaining was successful in 55.6%. Dilution of 1:200 resulted in the best possible evaluation of the tumor. The best suitable protocol was protocol B (phosphate buffered saline [PBS], without blocking agent). Melan A immunostaining was positive in 66.7%, the best dilution was 1:500 and protocol B (PBS, without blocking agent) was the most suitable. Ber-EP4 immunostaining presented a signal in 85.7%, the best dilutions were 1:200 and 1:500 and protocol A (PBS, with blocking agent) showed most optimal results.

CONCLUSION

The use of fluorescent-labeled antibodies in ex-vivo CLSM is possible and could improve intraoperative diagnostics of skin tumors.