Intraoral confocal microscopy of suspicious oral lesions: a prospective case series

State of the Art in the Diagnosis and Assessment of Oral Malignant and Potentially Malignant Disorders: Present Insights and Future Outlook-An Overview

Oral Potentially Malignant Disorder (OPMD) is a significant concern for clinicians due to the risk of malignant transformation. Oral Squamous Cell Carcinoma (OSCC) is a common type of cancer with a low survival rate, causing over 200,000 new cases globally each year. Despite advancements in diagnosis and treatment, the five-year survival rate for OSCC patients remains under 50%. Early diagnosis can greatly improve the chances of survival. Therefore, understanding the development and transformation of OSCC and developing new diagnostic methods is crucial. The field of oral medicine has been advanced by technological and molecular innovations, leading to the integration of new medical technologies into dental practice. This study aims to outline the potential role of non-invasive imaging techniques and molecular signatures for the early detection of Oral Malignant and Potentially Malignant Disorders.

Confocal microscopy in oral cancer and oral potentially malignant disorders: A systematic review

OBJECTIVE

To systematically identify and summarise current research on the utility of confocal microscopy in oral squamous cell carcinoma and oral epithelial dysplasia in oral potentially malignant disorders.

METHODS

Databases Medline, Embase, Evidence-Based Medicine, and Web of Science were searched with articles screened and included if their primary objective was the use of a confocal microscope in diagnosis of oral cancer or epithelial dysplasia, in vivo or ex vivo.

RESULTS AND DISCUSSION

Twenty-eight relevant studies were identified of which 21 studies included oral squamous cell carcinoma specimens. Fifteen studies included in vivo use. The studies included both qualitative and fluorescence confocal microscope and reflectance confocal microscope analysis along with quantitative analysis of carcinoma and dysplasia. Thirteen studies reported the predictive value of their confocal device in the diagnosis of dysplasia and carcinoma. The quantitative software-based studies show promise in objectifying the diagnostic process for identifying abnormalities within the microstructure of the oral mucosa.

CONCLUSIONS

There was heterogeneity in the criteria for diagnosis of dysplasia and oral squamous cell carcinoma with experience levels of assessors impacting method efficacy. Both qualitative and quantitative confocal assessment methodologies have been explored, the latter highlighting the potential of future machine-augmented diagnostic precision.

Personalized Medicine in Oral Oncology: Imaging Methods and Biological Markers to Support Diagnosis of Oral Squamous Cell Carcinoma (OSCC): A Narrative Literature Review

For decades, oral squamous cell carcinoma (OSCC) has been one of the most prevalent and mortal cancers worldwide. The gold standard for OSCC diagnosis is still histopathology but this narrative multidisciplinary review has the aim to explore the literature about conventional OSCC prognostic indicators related to the pTNM stage at the diagnosis such as the depth of invasion and the lymphovascular invasion associated with distant metastasis as indicators of poor life expectancy. Despite its multifactorial nature and recognizable precursors, its diagnosis at the early stages is still challenging. We wanted to highlight the importance of the screening as a primary weapon that a stomatologist should consider, intercepting all at-risk conditions and lesions associated with OSCC and its early stages. This narrative review also overviews the most promising imaging techniques, such as CT, MRI, and US-echography, and their application related to clinical and surgical practice, but also the most-investigated prognostic and diagnostic tissue and salivary biomarkers helpful in OSCC diagnosis and prognostic assessment. Our work highlighted remarkable potential biomarkers that could have a leading role in the future. However, we are still far from defining an appropriate and concrete protocol to apply in clinical practice. The hope is that the present and future research will overcome these limitations to benefit patients, clinicians, and welfare.

Acquisition and annotation in high resolution in vivo digital biopsy by confocal microscopy for diagnosis in oral precancer and cancer

Introduction

Scanned fibre endomicroscopes are full point-scanning confocal microscopes with submicron lateral resolution with an optical slice thickness thin enough to isolate individual cell layers, allow active positioning of the optical slice in the z-axis and collection of megapixel images. Here we present descriptive findings and a brief atlas of an acquisition and annotation protocol high resolution in vivo capture of oral mucosal pathology including oral squamous cell carcinoma and dysplasia using a fluorescence scanned fibre endomicroscope with 3 topical fluorescent imaging agents: fluorescein, acriflavine and PARPi-FL.

Methods

Digital biopsy was successfully performed via an acquisition protocol in seventy-one patients presenting for investigation of oral mucosal abnormalities using a miniaturized, handheld scanned fibre endoscope. Multiple imaging agents were utilized and multiple time points sampled. Fifty-nine patients had a matched histopathology correlating in location with imaging. The images were annotated back to macrographic location using a purpose-built software, MouthMap™.

Results

Acquisition and annotation of cellular level resolved images was demonstrated with all 3 topical agents. Descriptive observations between clinically or histologically normal oral mucosa showed regular intranuclear distance, a regular nuclear profile and fluorescent homogeneity. This was dependent on the intraoral location and type of epithelium being observed. Key features of malignancy were a loss of intranuclear distance, disordered nuclear clustering and irregular nuclear fluorescence intensity and size. Perinuclear fluorescent granules were seen in the absence of irregular nuclear features in lichenoid inflammation.

Discussion

High resolution oral biopsy allows for painless and rapid capture of multiple mucosal sites, resulting in more data points to increase diagnostic precision. High resolution digital micrographs can be easily compared serially across multiple time points utilizing an annotation software. In the present study we have demonstrated realization of a high-resolution digital biopsy protocol of the oral mucosa for utility in the diagnosis of oral cancer and precancer..

Role of reflectance confocal microscopy for in vivo investigation of oral disorders: White, red and pigmented lesions

In vivo reflectance confocal microscopy (RCM) is poorly investigated in oral pathology due to the peculiar anatomical and topographical oral mucosa features. A dedicated handheld confocal microscope with an intra-oral probe was developed for oral mucosa imaging. The main objective was to describe the healthy oral mucosa and the cytoarchitectural findings detectable in different oral disorders by means of the newly designed handheld confocal microscope. Secondary aim was to identify the main RCM criteria that differentiate oral lesions in order to provide algorithm for a rapid non-invasive evaluation. This observational retrospective study included all consecutive patients with oral disorders and volunteers with healthy oral mucosa who underwent RCM examination in our outpatient clinic from September 2018 to December 2021. Three different investigators examined together the RCM images to detect the key features and secondary criteria for each type of oral lesion collected. The study population included 110 patients affected by oral lesions and seven volunteers with healthy oral mucosae. A total of 15 oral disorders were imaged and divided in three main groups: white, red and pigmented lesions. Key features and secondary criteria were identified for every single type of oral disease. RCM permits a cytoarchitectural evaluation of the oral mucosae affected by inflammatory, dysplastic and neoplastic diseases, thus orienting the clinicians towards non-invasive diagnosis and enhancing the diagnostic management. The "tree diagrams" proposed allow a schematic and simplified view of confocal features for each type of oral disease, thus drastically reducing the diagnostic timing.

Optical Imaging in the Diagnosis of OPMDs Malignant Transformation

Oral potentially malignant disorders (OPMDs) are a heterogeneous group of oral lesions with a variable risk of malignant transformation to oral squamous cell carcinoma. The current OPMDs malignant transformation screening depends on conventional oral examination (COE) and is confirmed by biopsy and histologic examination. However, early malignant lesions with subtle mucosal changes are easily unnoticed by COE based on visual inspection and palpation. Optical techniques have been used to determine the biological structure, composition, and function of cells and tissues noninvasively by analyzing the changes in their optical properties. The oral epithelium and stroma undergo persistent structural, functional, and biochemical alterations during malignant transformation, leading to variations in optical tissue properties; optical techniques are thus powerful tools for detecting OPMDs malignant transformation. The optical imaging methods already used to detect OPMDs malignant transformation in vivo include autofluorescence imaging, narrowband imaging, confocal reflectance microscopy, and optical coherence tomography. They exhibit advantages over COE in detecting biochemical or morphologic changes at the molecular or cellular level in vivo; however, limitations also exist. This article comprehensively reviews the various real-time in vivo optical imaging methods used in the adjunctive diagnosis of OPMDs malignant transformation. We focus on the principles of these techniques, review their clinical application, and compare and summarize their advantages and disadvantages. Finally, we conclude with a discussion of current challenges and future directions of this field.

Algorithm mediated early detection of oral cancer from image analysis

OBJECTIVE

To develop Automatic Oral Cancer Detection algorithm for identification and differentiation of premalignant lesions from buccal cavity images for early detection of oral cancer, which may reduce related fatalities in developing countries.

STUDY DESIGN

The oral cavity images of normal, erythroplakia, and leukoplakia (20 images of each) were collected and processed using MATLAB image processing tools. First, maximum red value was used to differentiate between normal and abnormal. Second, mean red value was used for the selection of a processing path through YCbCr. Third, gray-level co-occurrence matrix (GLCM) based features were used to make final decisions. Images have been randomly divided and shuffled between training and test set to rigorously train the algorithm.

RESULTS

With 100% efficiency, normal images were separated from abnormal images in the first step by applying R value distribution with a cutoff R value, 11,900. Further, images with a mean R value >200 and <200 were processed by segmentation of Y plane and Cr plane, respectively. For the final decision, abnormal images were analyzed through the GLCM using the entropy feature as one of the key indicators, which can apply to the differentiation decision with 89% efficiency.

CONCLUSIONS

The developed algorithm can successfully differentiate premalignant lesions from normal. A graphic user interface was developed, which displays outcomes with reasonable accuracy.

Titanium Functionalized with Polylysine Homopolymers: In Vitro Enhancement of Cells Growth

In oral implantology, the success and persistence of dental implants over time are guaranteed by the bone formation around the implant fixture and by the integrity of the peri-implant mucosa seal, which adheres to the abutment and becomes a barrier that hinders bacterial penetration and colonization close to the outer parts of the implant. Research is constantly engaged in looking for substances to coat the titanium surface that guarantees the formation and persistence of the peri-implant bone, as well as the integrity of the mucous perimeter surrounding the implant crown. The present study aimed to evaluate in vitro the effects of a titanium surface coated with polylysine homopolymers on the cell growth of dental pulp stem cells and keratinocytes to establish the potential clinical application. The results reported an increase in cell growth for both cellular types cultured with polylysine-coated titanium compared to cultures without titanium and those without coating. These preliminary data suggest the usefulness of polylysine coating not only for enhancing osteoinduction but also to speed the post-surgery mucosal healings, guarantee appropriate peri-implant epithelial seals, and protect the fixture against bacterial penetration, which is responsible for compromising the implant survival.

Noninvasive Imaging Methods to Improve the Diagnosis of Oral Carcinoma and Its Precursors: State of the Art and Proposal of a Three-Step Diagnostic Process

Simple Summary

Oral squamous cell carcinoma (OSCC) accounts for 90–95% of malignant tumors of the lip and oral cavity and is associated with high mortality in the advanced stages. Early diagnosis is a challenge for oral pathologists and dentists, due to the ambiguous appearance of early OSCC, which is often misdiagnosed, mistreated, and associated with diagnostic delay. The gold standards for OSCC diagnosis are biopsy and histopathological assessment, but these procedures are invasive and time-consuming. Adjunctive noninvasive techniques allow the definition of the malignant features of a suspicious lesion in real time and noninvasively, thus improving the diagnostic procedure. The present review aimed to focus on some of the main promising noninvasive imaging techniques, to highlight their perspective adoption in a three-step diagnosis, which is idealistically faster and better, as well as enables the patient’s compliance.

Abstract

Oral squamous cell carcinoma (OSCC) is the most prevalent form of cancer of lips and oral cavity, and its diagnostic delay, caused by misdiagnosis at the early stages, is responsible for high mortality ratios. Biopsy and histopathological assessment are the gold standards for OSCC diagnosis, but they are time-consuming, invasive, and do not always enable the patient’s compliance, mainly in cases of follow-up with the need for more biopsies. The use of adjunctive noninvasive imaging techniques improves the diagnostic approach, making it faster and better accepted by patients. The present review aims to focus on the most consolidated diagnostic techniques, such as vital staining and tissue autofluorescence, and to report the potential role of some of the most promising innovative techniques, such as narrow-band imaging, high-frequency ultrasounds, optical coherence tomography, and in vivo confocal microscopy. According to their contribution to OSCC diagnosis, an ideal three-step diagnostic procedure is proposed, to make the diagnostic path faster, better, and more accurate.

Features of oral squamous cell carcinoma in ex vivo fluorescence confocal microscopy

BACKGROUND

Real-time microscopic imaging of freshly excised oral squamous cell carcinomas (OSCCs) would be potentially supportive in rapid recognition of oral malignancy and an optimal and time-saving management of patients' surgical treatment.

OBJECTIVES

The aim of this study was to examine oral squamous cell cancer tissue in regards to the commonly known and well-described histomorphologic criteria for the diagnosis of OSCC in ex vivo confocal fluorescent microscopy and to analyze its correlation with grade of differentiation and level of invasiveness.

METHODS

Ex vivo confocal laser scanning microscopy (CLSM) images of 38 OSCCs were evaluated immediately after excision for presence or absence of various cytological and architectural features based on the histopathological background. Next, these features were compared to the grade of differentiation as elaborated via gold standard histologic examination.

RESULTS

Of 38 invasive OSCCs, 14 were well differentiated, while three moderately and 19 were poorly differentiated. The presence of the commonly known cytologic and histopathologic criteria for the diagnosis of oral squamous cell carcinoma such as the destruction of the basal cell membrane, cellular and nuclear pleomorphism, anisocytosis, intraepithelial keratinization, nuclear hyperchromasia, atypical mitotic figures as well as the presence of necrosis, and mixed inflammation could be observed in ex vivo fluorescence confocal microscopy (FCM). In ex vivo fluorescence confocal microscopy pictures, cellular pleomorphism and anisocytosis were observed more often in poorly differentiated OSCCs. Intraepithelial keratinization was associated with well differentiated and moderately differentiated OSCCs.

CONCLUSION

The results demonstrate the high potential of ex vivo fluorescence confocal microscopy in fresh tissue for rapid real-time diagnosis of OSCC.

Reflectance confocal microscopy characteristics of oral lichen planus: An analysis of 47 cases in a Chinese cohort

Reflectance confocal microscopy (RCM) is a non-invasive tool that provides real-time microscopic images and relatively high-resolution tissue images. This technique provides a link between clinical examination and histopathology. RCM has been used to detect skin diseases and has also recently been applied to diseases of the oral mucosa. The present study aimed to explore the features of oral lichen planus (OLP) using RCM. A total of 47 patients with OLP exhibiting a reticular pattern, were included in the present study. The lesion sites and healthy adjacent sites were examined using in vivo RCM, with the lesion being histopathologically confirmed after RCM examination. The confocal images were reviewed, and the features were described. Sensitivity and specificity analysis of the RCM features was also performed. RCM examination presented parakeratosis, acanthosis and connective tissue papillae disappearance, with the presence of large melanocytes and roundish inflammatory cell infiltration, as well as dilated vessels in the lesion tissue. The sensitivity and specificity of OLP for dorsal tongue lesions were not as satisfactory as those on other sites. The results implied that RCM may be a promising technique to detect OLP non-invasively in vivo.

Real Time In Vivo Confocal Microscopic Analysis of the Enamel Remineralization by Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP): A Clinical Proof-of-Concept Study

Enamel defects (EDs) are qualitative and/or quantitative disturbances of the dental surface. To date, the responsiveness to remineralizing treatments has been studied ex vivo, on dental sections from extracted teeth. The present research aims to establish if in vivo reflectance confocal laser scanning microscopy is able to visualize the changes in the enamel architecture on living teeth, before, during and after remineralizing treatments by casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). As proof-of-concept study, 17 consecutive children affected by EDs were enrolled and 38 EDs were considered. A CPP-ACP mousse was applied twice a week for 6 weeks and clinical and microscopic images were collected before, during and after the treatment for evaluating the changes occurred. For in vivo microscopic imaging, a reflectance confocal laser scanning microscope (RCM) for in vivo use was adopted. In this study RCM was proven to be able to visualize in vivo and at microscopic resolution the changes occurred during the remineralizing processes without needing for dental extractions and histopathological procedures. This in vivo RCM capability could encourage its clinical application in monitoring responsiveness to enamel therapies.