Confocal Laser Endomicroscopy: A Primer for Pathologists

Abstract

N Context.-The advent of new endoscopic optical techniques is likely to change pathologists' role in diagnosis.Objective.-To describe how confocal laser endomicroscopy (CLE) works, show its advantages and limitations compared to cytohistologic biopsy, and explore how it may affect the practice of pathology.Data Sources.-Literature review.Conclusions.-Confocal laser endomicroscopy is proving its ability to provide histology-like images of tissues in vivo to help avoid risks and costs of conventional biopsies. Confocal imaging restricts light to 1 plane, emulating a paraffin section, and topical or systemic optical contrast agents allow subcellular resolution. New contrast agents could theoretically permit molecular characterization. In vivo imaging has begun to demonstrate novel, dynamic types of diagnostic features. Decreased histologic biopsies can be anticipated for a few scenarios. Significant limitations of CLE include the inability to create a tissue archive for broad molecular classification, suboptimal contrast agents, small fields of view and shallow penetration, paucity of clinical validation studies, and problems with reimbursement. Confocal laser endomicroscopy exposes new opportunities for pathologists: CLE technologies can be exploited in pathology, and diagnostic criteria expanded based on endoscopists' discoveries. Potential synergy exists between CLE and cytology, allowing the low-magnification diagnostic architectural changes by CLE and cytomorphology to emulate the full diagnostic information in a histologic biopsy while providing an archive of material for molecular or immunohistochemical studies. Confocal laser endomicroscopy will decrease some types of biopsies, but offers an opportunity for pathologists to find new ways to provide value and improve patient care.

Confocal laser endomicroscopy in head and neck cancer

“…Apart from these nonspecific stains, fluorescing probes directed against certain disease-specific biomarkers are being investigated in experimental settings [1]. The successful use of mAbs targeted against the epidermal growth factor receptor (EGFR) or vascular endothelial growth factor (VEGF) has been reported in organ cultures, tissue samples and human tumours grown in mice [31][32][33].…”

“…CLE allows high-resolution, microanatomical analysis of tissue ('optical biopsies') in real time during endoscopy [1,2]. The utility of this new technology is highlighted by its capacity to differentiate tissue types and entities on the basis of histologic characteristics of the mucosa and submucosal vasculature [3].…”

Biomedical Optics and Lasers

“…Depending on the laser source and application modes diagnostic data can be yielded via optical information of ultra-high resolution even in deep organ systems via ultra-thin endoscopic probes, which makes confocal laser microscopy inevitable for the physicians who are responsible to diagnose any kind of malignant tumor [99]. So that tissue discrimination and manifold types of fluorescence detection can be achieved.…”

Optical configuration of pigmented lesion detection by frequency analysis of skin speckle patterns

“…These optical methods, i.e. 'optical biopsy' methods [22,23], such as fluorescence endoscopy [24], optical coherence tomography (OCT) [25,26] and confocal microendoscopy [27,28], were developed in order to extract a three-dimensional cross section, avoiding the diffuse reflected light. However, these methods are very complicated and heavily depend on the expertise of the researcher.…”