Ex vivo confocal laser scanning microscopy for bullous pemphigoid diagnostics: new era in direct immunofluorescence?

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.

Alkubaisy S, A. Sattar D, S. Hamzah S, Hadi Saleh T, Laftaah Al-Rubaii BA. Detection of anti-testicular antibodies among infertile males using indirect immunofluorescent technique

Introduction and Aim: The antinuclear antibodies (ANA) are unwanted molecules which bind and destroy certain structures within the nucleus. Immunofluorescence is a powerful technique that utilizes fluorescent-labeled antibodies to detect specific target antigens. The aim of this study was to detect the anti-testicular antibody among infertile males in Baghdad city and determine the most common type of infertility.   Materials and Methods: The study involved 73 male (53 infertile and 20 non-infertile) volunteers, at Kamal Al-Samarrai Teaching Hospital in Baghdad, Iraq. Serum collected from the study subjects was tested for steroid-cell antibodies (STC-Ab), anti-nuclear antibody (ANA) and anti-testicular antibodies (ATCA) by Indirect Immunofluorescence assay (IIFA). Data obtained was subjected to statistical analysis using the SPSS program.   Results: In the current study 52.9% of infertile men tested positive for testicular antibodies compared to the control group. The highest rate of testicular cell antibodies was observed in the serum of infertile patients aged between 30-39 years and the lowest in patients aged 50-59 years. The marriage duration among those showing the highest percentage of antibodies against testicular cells was 1-10 years. Study for the association of male infertility type to those positive for ATCA showed almost all (85.7%) patients with necrozoospermia to be positive for ATCA. This was followed by males with azoospermia (50%) and oligospermia (46.9%). The patients were negative for Addison’s disease while a few (28.6%) were positive for lupus erythematosus.

Ex vivo fluorescence confocal microscopy: chances and changes in the analysis of breast tissue

Background

Rapid histologic diagnosis of frozen sections is essential for a variety of surgical procedures. Frozen sections however, require specialized lab equipment, are prone to freezing artifacts and are not applicable to all types of tissue. Adipose tissue is especially difficult to process in frozen sections. Although these limitations are well known, no alternative method for microscopic tissue analysis that might replace frozen sections could be established. Our objective was to evaluate whether tissue imaging based on ex vivo fluorescent confocal microscopy (FCM) is applicable for rapid microscopic assessment of breast tumors specimens with abundant adipose tissue.

Methods

We evaluated 17 tissue samples from mastectomy specimens, rich in adipose tissue, submitted to the department of pathology at the Medical University of Vienna. We conducted our study on the FCM VivaScope® 2500M-G4 (Mavig GmbH, Munich, Germany; Caliber I.D.; Rochester NY, USA).

Results

When comparing FCM to frozen sections, we found a very similar overall processing time for FCM images and frozen sections respectively. Image quality was mostly superior to frozen sections (especially for adipose tissue and nuclear detail) but inferior to H&E stained FFPE sections. Limitations of the technology were uneven coloring, invisibility of ink applied for marking tissue margins and distortion artifacts if too much pressure is applied to the tissue.

Conclusion

FCM has the potential to expand the application and usefulness of rapid tissue analysis as speed is comparable and quality exceeds that of frozen sections especially in tissues rich in adipose cells such as breast specimen.

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.

Visualization of energy-based device-induced thermal tissue alterations using bimodal ex-vivo confocal microscopy with digital staining. A proof-of-concept study

BACKGROUND

Ex-vivo confocal microscopy (EVCM) enables examination of tissue alterations immediately after treatment with energy-based devices (EBDs). This proof-of-concept study aimed to describe EBD-induced tissue effects in ex-vivo porcine skin after treatment with microneedle radiofrequency (MNRF) and ablative fractional CO₂ -laser (AFL) using EVCM.

MATERIALS AND METHODS

Ex-vivo porcine skin was treated with MNRF and AFL. Three cryosections from each intervention were stained with acridine orange (AO) and scanned with EVCM. Reflectance confocal microscopy (RCM, 638 nm) and fluorescence confocal microscopy (FCM, 488 nm) images were captured and evaluated individually, after image fusion, and after digital hematoxylin and eosin (H&E) staining.

RESULTS

Bimodal EVCM was able to visualize EBD-induced thermal alterations in porcine skin. In RCM mode, the full width and depth of the vertically aligned microscopic treatment zones (MTZs) were displayed with clear demarcation to surrounding intact skin. In FCM mode, the ablation of the epidermis after AFL was prominent in contrast with the almost intact epidermis observed in MNRF treated skin. In fusion mode, fluorescence signal from AO marked the surrounding coagulation zone (CZ) from both interventions, with enhanced discrimination between ablation and coagulation. Digitally H&E-stained images closely resembled conventional histopathology but proved superior in terms of visualization of the CZ.

CONCLUSION

Bimodal EVCM with digital H&E-staining facilitates the identification and qualitative evaluation of thermal alterations induced by treatment with EBD. By providing high-resolution images comparable to standard histology, EVCM is a useful tool in the research and development of EBD to visualize and evaluate device-tissue interactions.

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.

Classification of Basal Cell Carcinoma in Ex Vivo Confocal Microscopy Images from Freshly Excised Tissues Using a Deep Learning Algorithm

Ex vivo confocal microscopy (EVCM) generates digitally colored purple-pink images similar to H&E without time-consuming tissue processing. It can be used during Mohs surgery for rapid detection of basal cell carcinoma (BCC); however, reading EVCM images requires specialized training. An automated approach using a deep learning algorithm for BCC detection in EVCM images can aid in diagnosis. A total of 40 BCCs and 28 negative (not-BCC) samples were collected at Memorial Sloan Kettering Cancer Center to create three training datasets: (i) EVCM image dataset (663 images), (ii) H&E image dataset (516 images), and (iii) a combination of the two datasets. A total of seven BCCs and four negative samples were collected to create an EVCM test dataset (107 images). The model trained with the EVCM dataset achieved 92% diagnostic accuracy, similar to the H&E model (93%). The area under the receiver operator characteristic curve was 0.94, 0.95, and 0.94 for EVCM-, H&E-, and combination-trained models, respectively. We developed an algorithm for automatic BCC detection in EVCM images (comparable accuracy to dermatologists). This approach could be used to assist with BCC detection during Mohs surgery. Furthermore, we found that a model trained with only H&E images (which are more available than EVCM images) can accurately detect BCC in EVCM images.

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.

Simultaneous immunofluorescence and histology in pemphigus vulgaris using ex vivo confocal laser scanning microscopy

Ex vivo confocal laser scanning microscopy (ex vivo CLSM) provides rapid, high-resolution imaging and immunofluorescence examinations of the excised tissues. We aimed to evaluate the applicability of ex vivo CLSM in histomorphological and direct immunofluorescence (DIF) examination of pemphigus vulgaris (PV). 20 PV sections were stained with fluorescent-labeled anti-IgG and anti-C3 using various dilutions and incubation periods. Subsequently, the determined ideal staining protocol was applied on 20 additional PV and 20 control sections. Ex vivo CLSM identified intraepidermal blisters and acantholytic cells in 80% and 60% of PV patients, respectively. The sensitivity of ex vivo CLSM in detecting intraepidermal fluorescence was 90% both with IgG and C3. The specificity of staining for IgG and C3 was 70% and 90%, respectively. Histomorphological and immunofluorescence features of PV could be detected within the same ex vivo CSLM session showing a comparable performance to conventional histopathology and DIF microscopy.

Line field confocal optical coherence tomography: An adjunctive tool in the diagnosis of autoimmune bullous diseases

Autoimmune bullous diseases (AIBDs) still represent a considerable a source of morbidity and mortality: early identification of a specific AIBD is often difficult due to overlapping clinical and/or laboratory features and time-consuming invasive laboratory tests. We aimed to investigate the potential role of a new imaging technology, line-field confocal optical coherence tomography (LC-OCT), in the non-invasive diagnosis of AIBDs. LC-OCT was performed at lesional, perilesional and contralateral healthy sites in 30 patients, before histology and direct immunofluorescence. LC-OCT examination was able to identify the level of split (subcorneal/suprabasal/subepidermal/sublamina densa), to provide detailed images of the bulla roof morphology and content (eg, erythrocytes/acantholytic cells/polymorphonucleates). Areas of intra/subepidermal detachment were also detected also at clinically normal perilesional skin sites. LC-OCT can support physicians, real time and at bed-site, in the differential diagnosis of various AIBDs and their mimickers. Moreover, it can be used for the identification of subclinical lesions and therapy tapering.

Routine application of ex vivo confocal laser scanning microscopy with digital staining for examination of surgical margins in basal cell carcinomas

BACKGROUND AND OBJECTIVES

Ex vivo confocal laser scanning microscopy (CLSM) allows histologic examination of native tissue based on tissue reflection and nuclear fluorescence staining. The newly introduced digital staining process almost perfectly mimics conventional hematoxylin and eosin (HE) slides. The aim was to evaluate the new method in clinical routine, with regard to quality of findings and time requirements, in the examination of surgical margins of basal cell carcinomas.

PATIENTS AND METHODS

78 patients with 101 basal cell carcinomas were prospectively enrolled. Surgery was performed either with complete margin control (n = 60) or as elliptical excision (n = 41). Immediately after excision specimens were scanned with CLSM and then routinely processed by conventional histopathology. Blinded evaluation of images and slides was performed by a dermatopathologist.

RESULTS

Basal cell carcinomas were excellently recognizable by CLSM directly after excision, and the use of digital staining did not require any adjustment of the examiner's visualization preferences. CLSM images showed a sensitivity of 73.6 % and a specificity of 96.5 % compared to conventional HE stained slides. Erroneous findings were often due to limited assessment potential in cases where the epidermis could not be fully visualized.

CONCLUSIONS

CLSM with digital HE staining is very well suited to diagnose basal cell carcinomas and their incision margins even under routine conditions and thus represents a tissue-saving alternative to rapid cryostat sectioning.

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.

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.

Immune serological diagnosis of pemphigus

Pemphigus is a rare autoimmune blistering disease which manifests with painful erosions and blisters of the skin and mucosa. This disorder is caused by autoantibodies attacking desmosomal proteins, necessary for cell-cell contact stability and epidermal integrity. Desmoglein (Dsg) 1 and Dsg3 are the two major target antigens in pemphigus. Yet, many other target proteins, which have been described over the years, seem to be involved in the loss of epidermal integrity. Clinical examination, combined to serological advances and detection of targeted antigens, permitted to differentiate among several pemphigus subtypes, in which pemphigus vulgaris and pemphigus foliaceus are the most common. Nowadays, serological analysis in pemphigus is a fundamental step of the diagnostic algorithm. This is based on analysis of clinical symptoms, histopathological examination of lesional skin, detection of tissue bound and circulating antibodies by direct and indirect immunofluorescence, and determination of target antigens either by enzyme-linked immunosorbent essay (ELISA) or by western blot analysis. A correct and exhaustive diagnostic algorithm is fundamental to characterize pemphigus subtypes, which lastly permits to adopt a correct treatment approach. Moreover, quality and quantity of circulating antibodies in patient's sera deliver important information regarding clinical course, disease severity and treatment response; thus, relevantly affecting physician's decision. To facilitate this process, "easy-to-perform" diagnostic kits with high sensitivity and specificity are being commercialized. In this review, we focus on available methods and established assays to correctly detect circulating autoantibodies in pemphigus. Moreover, we discuss subtype specific serological peculiarities in the five most relevant subtypes (pemphigus vulgaris, pemphigus foliaceus, pemphigus vegetans, paraneoplastic pemphigus and intercellular IgA dermatosis (also called as IgA pemphigus).

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.

Recurrence of Pemphigus Vulgaris Under Nivolumab Therapy

For many types of cancer, immune checkpoint inhibitors have proven to be a highly effective treatment. The monoclonal anti-PD-1 antibody nivolumab stimulates the immune system and is one of the newest treatment options for non-small cell lung cancer. In doing so, immune checkpoint inhibitors can trigger many skin lesions that have not yet been completely investigated in their entirety. In this case report, pemphigus vulgaris is identified as a potential adverse event that occurs under the treatment with nivolumab. In addition to the standard methods, we examined our patient's samples with ex vivo confocal laser scanning microscopy. This is a new and innovative diagnostic method that uses vertical scanning to provide fast, high-resolution imaging of freshly excised tissue, even using fluorescently labeled antibodies.