Impact of intraepithelial capillary loops and atypical vessels in confocal laser endomicroscopy for the diagnosis of laryngeal and hypopharyngeal squamous cell carcinoma

Abstract

Purpose Confocal laser endomicroscopy (CLE) allows surface imaging of the laryngeal and pharyngeal mucosa in vivo at a thousand-fold magnification. This study aims to compare irregular blood vessels and intraepithelial capillary loops in healthy mucosa and squamous cell carcinoma (SCC) via CLE. Materials and methods We included ten patients with confirmed SCC and planned total laryngectomy in this study between March 2020 and February 2021. CLE images of these patients were collected and compared with the corresponding histology in hematoxylin and eosin staining. We analyzed the characteristic endomicroscopic patterns of blood vessels and intraepithelial capillary loops for the diagnosis of SCC. Results In a total of 54 sequences, we identified 243 blood vessels which were analyzed regarding structure, diameter, and Fluorescein leakage, confirming that irregular, corkscrew-like vessels (24.4% vs. 1.3%; P < .001), dilated intraepithelial capillary loops (90.8% vs. 28.7%; P < .001), and increased capillary leakage (40.7% vs. 2.5%; P < .001), are significantly more frequently detected in SCC compared to the healthy epithelium. We defined a vessel diameter of 30 μm in capillary loops as a cut-off value, obtaining a sensitivity, specificity, PPV, and NPV and accuracy of 90.6%, 71.3%, 57.4%, 94.7%, and 77.1%, respectively, for the detection of malignancy based solely on capillary architecture. Conclusion Capillaries within malignant lesions are fundamentally different from those in healthy mucosa regions. The capillary architecture is a significant feature aiding the identification of malignant mucosa areas during in-vivo, real-time CLE examination.

Oral mucosa - an examination map for confocal laser endomicroscopy within the oral cavity: an experimental clinical study

“…Overall, the images within our study showed an increased number of blood vessels in the lip mucosa. However, there were no malignant features of the vascular structure (like corkscrew-like vessels or dilated intraepithelial capillary loops) as described in a previous study by our research group [ 21 ]. This supports the assumption that these are physiological mucosal areas, consistent with the clinical appearance (even without histological confirmation).…”

Validity of tissue homogeneity in confocal laser endomicroscopy on the diagnosis of laryngeal and hypopharyngeal squamous cell carcinoma

“…In a previous study about the diagnostic value of intraepithelial capillary loops and atypical vessels in SCC diagnosis, we demonstrated that a cutoff value for vessel diameter of 30 μm enables the diagnosis of SCC with a sensitivity and specificity of, respectively, 90.6% and 71.3% [ 29 ]. However, while both criteria, tissue homogeneity and vessel diameter, as stand-alone diagnostic features, provide good sensitivity and specificity values, its diagnostic metrics are still inferior to diagnostic scores that integrate both features [ 17 ].…”

Development, Implementation and Application of Confocal Laser Endomicroscopy in Brain, Head and Neck Surgery—A Review

“…White et al first described the applicability of CLE in the head and neck region in 1999 using six healthy control tissue specimens and described its morphological similarity with corresponding H&E-stained microscopic sections [ 54 ]. This first description of CLE imaging in the head and neck area was followed by numerous in vitro [ 55 , 56 , 57 , 58 , 59 , 60 ] and in vivo studies [ 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 ] focusing on the noninvasive detection of head and neck cancer using CLE. Table 2 gives an overview of the most important in vitro and in vivo studies on CLE applications in the head and neck region over the past 23 years.…”

“…From 2016 on, systemically applied fluorescein (i.v. application) was used in nearly all published CLE in vivo studies in the head and neck region and presumably provides the best tissue contrast and quality of generated CLE images [ 81 , 82 , 83 , 84 , 88 , 89 , 90 , 91 ]. Further studies have to show if other fluorescent dyes, e.g., indocyanine green, can potentially enhance tissue contrast even more.…”

“…Nearly all studies confirmed a good correlation between CLE morphology and histology and stated a relevant benefit for the intraoperative evaluation and the surgical management of suspicious mucosal lesions [ 54 , 68 , 72 ]. The most relevant morphological criteria for accurate differentiation between tumor and healthy tissue include tissue homogeneity, cell size, borders and clusters, intraepithelial capillary loops, atypical vessels, and the nucleus/cytoplasm ratio [ 81 , 82 , 89 , 90 , 91 ]. Based on these observations, Sievert et al developed CLE imaging scores assessing different combinations of the aforementioned morphological characteristics for laryngeal, pharyngeal, and oral cavity squamous cell carcinomas [ 81 , 82 , 91 ].…”