Handheld In Vivo Reflectance Confocal Microscopy for the Diagnosis of Eyelid Margin and Conjunctival Tumors

[Evaluation of the accuracy of clinical diagnosis of conjunctival neoplasms : Comparison with histological findings after excision]

BACKGROUND

Neoplasms of the conjunctiva include many different entities with a broad variety of clinical presentations. This can make a precise clinical diagnosis difficult. R0 resection is the gold standard treatment for most malignant conjunctival neoplasms, but not every benign lesions must treated by excision. In clinical practice it is important to make an accurate clinical diagnosis to enable the best possible management of conjunctival neoplasms.

OBJECTIVE

The aim of this study was to determine the accuracy of clinical diagnosis of neoplasms of the conjunctiva.

MATERIALS AND METHODS

Within a retrospective design, the data from all patients with excision of a conjunctival lesion between 2011 and 2020 in the Department of Ophthalmology of the UKSH Campus Kiel were extracted and analyzed. The specificity, sensitivity, and positive and negative predictive value for the preoperative clinical rating of dignity and diagnosis were evaluated based on the histological diagnostic findings.

RESULTS

Of 220 included cases, 75% were benign and 25% malignant. The most frequent neoplasm of the conjunctiva was benign conjunctival nevus. The sensitivity for clinical prediction of a benign lesion was 0.86 (95% confidence interval [CI] 0.59-0.92), the specificity 0.95 (CI 0.85-0.99), and the positive predictive value 0.98 (CI 0.94-1.0). The sensitivity for clinical prediction of malign dignity was 0.95 (CI 0.85-0.99), the specificity 0.88 (CI 0.83-0.93), and the positive predictive value 0.73 (CI 0.61-0.83).

CONCLUSION

The derived values for clinical diagnosis of conjunctival neoplasms can be rated as good. However, in clinical practice, untypical lesions can be hard to diagnose correctly, and the clinical diagnosis should be carefully reviewed; if in doubt, excision should be preferred.

Noninvasive Imaging of Conjunctival Goblet Cells as a Method for Diagnosing Dry Eye Disease in an Experimental Mouse Model

Purpose

The purpose of this study was to evaluate a noninvasive conjunctival goblet cell (GC) imaging method for assessing dry eye disease (DED) in an experimental mouse model.

Methods

Moxifloxacin-based fluorescence microscopy (MBFM) was used to examine GCs noninvasively in 56 mice. Forty-two (42) DED-induced mice were divided into 2 groups and treated topically for 14 days with cyclosporine (CsA) or normal saline (NS). In vivo MBFM imaging and clinical DED evaluations were performed and goblet cell density (GCD) and goblet cell area (GCA) were obtained and compared with histological GCD using periodic acid-Schiff (PAS) staining. Correlation and receiver operating characteristic (ROC) analyses showed MBFM's high diagnostic value.

Results

The GCD and GCA of the DED mice obtained from in vivo MBFM imaging were highly correlated with clinical DED parameters and GCD obtained from PAS histology. The therapeutic effect of CsA, as observed by in vivo MBFM, was significant with respect to that of NS treatment. The ROC curves derived from in vivo MBFM showed high diagnostic value in assessing DED.

Conclusions

The proposed noninvasive method has high diagnostic value in assessing the severity of DED and the effect of treatment for this disease.

Translational Relevance

A noninvasive imaging method using moxifloxacin-based fluorescence microscopy was evaluated for assessing DED in an experimental mouse model. The method showed high diagnostic value in assessing the severity of DED and the effect of treatment, bridging the gap between basic research and clinical treatment. The study provides a promising tool for diagnosing and monitoring DED.

Morphological characterization of nevi on the caruncle conjunctiva under in vivo confocal microscopy

Objective

This study aimed to investigate the microscopic structure and characteristics of nevi on the conjunctiva of the lacrimal caruncle by in vivo confocal microscopy.

Methods

In total, four patients with nevi growing on the lacrimal caruncle conjunctiva were recruited. The morphological characteristics of the nevi were evaluated by in vivo confocal microscopy before excision surgery; the results were compared with histopathological analyses of the surgical specimens.

Results

The nevi of the four patients were all located at the conjunctiva of the lacrimal caruncle, with a slightly nodular surface, mixed black and brown color, and clear boundary. The nevi were round and highly protruded on the surface of the lacrimal caruncle, with an average diameter of 4.5 ± 1.29 mm. Under in vivo confocal microscopy, the pigmented nevus cells on the conjunctiva of the lacrimal caruncle were observed to be clustered in nests with irregular boundaries. The cells were round or irregular, with clear cell boundaries, hyper-reflective at the periphery, with low reflectivity in the center. Vascular crawling was observed in some regions. Histopathological analysis showed that nevus cells were roughly equal in size and distributed in a nodular pattern. Melanin granules were observed in the cytoplasm. No atypia or mitotic figures of the cells were found.

Conclusion

This study revealed that the microstructure of nevi growing on the conjunctiva of the lacrimal caruncle can be identified by in vivo confocal microscopy.

Slit lamp polarized dermoscopy: a cost-effective tool to assess eyelid lesions

PURPOSE

Dermoscopy is a complementary examination of skin lesions, which allows the observation of anatomical features invisible to the naked eye. Its use increases the diagnostic accuracy of skin tumors. The development of polarized dermoscopy allowed the observation of deeper skin structures, without the need of skin contact. The purpose of this study was to present a low-cost prototype through the adaptation of polarized lenses on a slit lamp in order to assess anatomical aspects invisible to conventional biomicroscopy in eyelid lesions.

METHODS

Twenty two eyelid lesions were documented using a prototype, compound of two polarizing filters, orthogonal to each other, adapted to a slit lamp with an integrated digital camera. Images of the eyelid lesions were also obtained with non-polarized biomicroscopy and with a portable dermatoscope, and were compared regarding anatomical aspects.

RESULTS

Anatomical structures imperceptible to conventional ophthalmic examination were evidenced using the polarized lenses, demonstrating that this tool can be useful to the ophthalmologist when assessing eyelid lesions. We have obtained high-quality images of the lesions. The slit lamp provided higher magnification, better focus control and easier assessment of eyelid lesions than the portable dermatoscope.

CONCLUSION

Ophthalmologists already use the slit lamp in their practice. The adaptation of polarized lenses to this device is a cost-effective, fast and non-invasive method that permits to improve the diagnostic accuracy of eyelid lesions, evidencing anatomical structures imperceptible to conventional ophthalmic examination.

Moxifloxacin-Based Extended Depth-of-Field Fluorescence Microscopy for Real-Time Conjunctival Goblet Cell Examination

Conjunctival goblet cells (CGCs) are mucin-secreting cells in the eye and play essential roles for ocular surface homeostasis. Since various ocular surface pathologies are related to CGC dysfunction, CGC examination is important for the evaluation of ocular surface conditions. Recently we introduced moxifloxacin-based fluorescence microscopy (MBFM) for non-invasive CGC imaging. However, the imaging speed was up to 1 frame per second (fps) and needed to be improved for clinical applications. In this study, we developed a high-speed moxifloxacin-based, extended depth-of-field (EDOF) microscopy system that operates at a maximum imaging speed of 15 fps. The system used a deformable mirror for the high-speed axial sweeping of focal plane during single-frame acquisitions. The acquired images contained both in-focus and out-of-focus information, and deconvolution was used to filter the in-focus information. The system had a DOF of 800 [Formula: see text], field-of-view of 1.2 mm ×1.2 mm, and resolution of [Formula: see text]. Its performance was demonstrated by real-time, breathing-motion-insensitive CGC imaging of mouse and rabbit models, in vivo. High-speed EDOF microscopy has potentials for non-invasive, real-time CGC examinations of human subjects.

New Therapeutic Approaches for Conjunctival Melanoma-What We Know So Far and Where Therapy Is Potentially Heading: Focus on Lymphatic Vessels and Dendritic Cells

Conjunctival melanoma (CM) accounts for 5% of all ocular melanomas and arises from malignantly transformed melanocytes in the conjunctival epithelium. Current therapies using surgical excision in combination with chemo- or cryotherapy still have high rates for recurrences and metastatic disease. Lately, novel signal transduction-targeted and immune checkpoint inhibitors like cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, programmed cell death protein-1 (PD-1) receptor inhibitors, BRAF- or MEK-inhibitors for systemic treatment of melanoma have improved the outcome even for unresectable cutaneous melanoma, improving patient survival dramatically. The use of these therapies is now also recommended for CM; however, the immunological background of CM is barely known, underlining the need for research to better understand the immunological basics when treating CM patients with immunomodulatory therapies. Immune checkpoint inhibitors activate tumor defense by interrupting inhibitory interactions between tumor cells and T lymphocytes at the so-called checkpoints. The tumor cells exploit these inhibitory targets on T-cells that are usually used by dendritic cells (DCs). DCs are antigen-presenting cells at the forefront of immune response induction. They contribute to immune tolerance and immune defense but in the case of tumor development, immune tolerance is often prevalent. Enhancing the immune response via DCs, interfering with the lymphatic pathways during immune cell migration and tumor development and specifically targeting tumor cells is a major therapeutic opportunity for many tumor entities including CM. This review summarizes the current knowledge on the function of lymphatic vessels in tumor growth and immune cell transport and continues to compare DC subsets in CM with related melanomas, such as cutaneous melanoma and mucosal melanoma.

Multi-Focus Image Fusion Using Focal Area Extraction in a Large Quantity of Microscopic Images

The non-invasive examination of conjunctival goblet cells using a microscope is a novel procedure for the diagnosis of ocular surface diseases. However, it is difficult to generate an all-in-focus image due to the curvature of the eyes and the limited focal depth of the microscope. The microscope acquires multiple images with the axial translation of focus, and the image stack must be processed. Thus, we propose a multi-focus image fusion method to generate an all-in-focus image from multiple microscopic images. First, a bandpass filter is applied to the source images and the focus areas are extracted using Laplacian transformation and thresholding with a morphological operation. Next, a self-adjusting guided filter is applied for the natural connections between local focus images. A window-size-updating method is adopted in the guided filter to reduce the number of parameters. This paper presents a novel algorithm that can operate for a large quantity of images (10 or more) and obtain an all-in-focus image. To quantitatively evaluate the proposed method, two different types of evaluation metrics are used: “full-reference” and “no-reference”. The experimental results demonstrate that this algorithm is robust to noise and capable of preserving local focus information through focal area extraction. Additionally, the proposed method outperforms state-of-the-art approaches in terms of both visual effects and image quality assessments.

Use of Reflectance Confocal Microscopy for Hidrocystomas: An Emerging, Cost-Effective, and Powerful Tool

Reflectance confocal microscopy (RCM) is an emerging and noninvasive imaging tool in dermatological practice. Benefits of this modality include differentiation between benign and malignant skin lesions, prevention of unnecessary biopsies, and cost effectiveness. However, RCM findings for benign lesions are rarely reported in the literature. We describe a case of reflectance confocal microscopy findings of a hidrocystoma and review potential applications of this imaging technique in everyday clinical practice.

Review of Dermoscopy and Reflectance Confocal Microscopy Features of the Mucosal Melanoma

Mucosal melanoma is a rare tumor with aggressive biological behavior and poor prognosis. Diagnosis is often performed at an advanced stage when the lesions become symptomatic. Although dermoscopy and reflectance confocal microscopy (RCM) are widely used techniques for the diagnosis of cutaneous tumors, their use for mucosal lesions is not well established, probably because the latter are rarer. The objective of this study was to evaluate current literature on these imaging techniques for mucosal melanoma. We searched in PubMed and Cochrane databases all studies up to October 2020 dealing with dermoscopy, RCM, and mucosal melanoma. We found that the most relevant dermoscopic features were structureless pattern and/or the presence of multiple colors. RCM examination mainly showed numerous basal hyper-reflective dendritic cells and loss of normal architecture of the papillae of the lamina propria. Although diagnostic algorithms have been proposed for both techniques, the limit of these methods is the absence of large studies and of standardized and shared diagnostic criteria.

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.

Current Management of Conjunctival Melanoma Part 1: Clinical Features, Diagnosis and Histopathology

Conjunctival melanoma is a rare disease which makes up approximately 5% of ocular melanomas. The lesion may occur de novo or originate from a pre-existing nevus or primary acquired melanosis. Biomicroscopy is of paramount importance in diagnosis and follow-up of the disease, while other diagnostic modalities serve as supplementary tools. Many clinical and histopathological risk factors have been reported for prognosis. This review aims to address the clinical findings, differential diagnosis, diagnostic tools, prognostic factors, and staging of this disease.

Moxifloxacin based axially swept wide-field fluorescence microscopy for high-speed imaging of conjunctival goblet cells

Goblet cells (GCs) in the conjunctiva are specialized epithelial cells producing mucins on the ocular surface. GCs play important roles in maintaining homeostasis of the ocular surface, and GC dysfunction is associated with various complications including dry eye diseases. Current GC examination methods, which are conjunctival impression cytology and confocal reflection microscopy, have limitations for routine examination. Fluorescence microscopy using moxifloxacin was recently introduced as a non-invasive and high-contrast imaging method, but further development is needed to be used for GC examination. Here we developed a non-invasive high-speed high-contrast GC imaging method, called moxifloxacin based axially swept wide-field fluorescence microscopy (MBAS-WFFM). This method acquired multiple fluorescence images with the axial sweeping of the focal plane to capture moxifloxacin labeled GCs on the tilted conjunctival surface in focus and generated all-in-focus images by combining the acquired images. The imaging field of view and imaging speed were increased to 1.6 mm × 1.6 mm and 30 fps. An image processing method was developed for the analysis of GC density. MBAS-WFFM was applied to alkali burn mouse models and detected GC damage and recovery via longitudinal imaging. MBAS-WFFM could assess the status of GCs rapidly and non-invasively. We anticipate MBAS-WFFM to be a starting point for non-invasive GC examination and the diagnosis of GC associated diseases. For example, MBAS-WFFM could be used to classify dry eye diseases into detail categories for effective treatment.

Reflectance confocal microscopy terminology glossary for melanocytic skin lesions: A systematic review

BACKGROUND

There is lack of uniformity in the reflectance confocal microscopy (RCM) terminology for melanocytic lesions.

OBJECTIVE

To review published RCM terms for melanocytic lesions and identify redundant, synonymous terms.

METHODS

A systematic review of original research articles adhering to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines was conducted until August 15, 2018. Two investigators gathered all published RCM terms used to describe melanoma and melanocytic nevi. Synonymous terms were grouped based on similarity in definition and in histopathologic correlation.

RESULTS

Out of 156 full-text screened articles, 59 studies met the inclusion criteria. We identified 209 terms; 191 (91.4%) corresponding to high-magnification/cellular-level terms and 18 (8.6%) corresponding to low-magnification/architectural patterns terms. The overall average use frequency of RCM terms was 3.1 times (range, 1-31). By grouping of individual RCM terms based on likely synonymous definitions and by eliminating terms lacking clear definition, the total number of RCM terms could be potentially reduced from 209 to 40 terms (80.8% reduction).

LIMITATIONS

Non-English and non-peer-reviewed articles were excluded.

CONCLUSIONS

This systematic review of published RCM terms identified significant terminology redundancy. It provides the basis for subsequent terminology consensus on melanocytic neoplasms.

How transparent film applied on dermatologic imaging devices in order to prevent infections affects image quality?

BACKGROUND

In the clinical practice, transparent films are used as sterile interfaces in in vivo dermatologic imaging in order to prevent the transmissions of infections. However, in our experience, the use of a transparent film can alter skin images. Our study aimed to compare the optical quality of a series of different plastic films used as interfaces in order to understand if some might be more suitable for imaging.

MATERIALS AND METHODS

We tested the optical properties of 11 different protective transparent films that are marketed in France with a transparency meter and a spectrophotometer.

RESULTS

Transmission, minimal diffusion, amount of gray, and contrast were obtained for each transparent film. Transmission ranged from 93.24% to 96.88% (mean 95.36; standard deviation SD 1.02), minimal diffusion from 88.28% to 123.87% (mean 101.04; standard deviation SD 10.02) and contrast from 11.01 to 15.88 (mean 13.93 and SD 1.3). For some films, the transmission was lower at lower wavelengths.

CONCLUSION

All tested films had excellent optical properties. However, some of them had better optical qualities and seemed more suitable for their use in dermatologic imaging.