Histologic assessment of epithelial thickness in early laryngeal cancer or precursor lesions and its impact on endoscopic imaging

Abstract

The objective of the study was to assess the epithelial thickness in different lesions of the vocal folds in order to gain more information about its influence on endoscopic imaging. Retrospective study including 161 patients undergoing surgery for a total of 206 benign and malignant lesions of the vocal folds. Laryngoscopy and autofluorescence endoscopy were the first line of investigation for these lesions. Diagnosis was confirmed by histopathology in all cases. Morphometric measurement of epithelial thickness was performed using a normal white light and an autofluorescence microscope. The vocal fold mucosa revealed a progressive thickening from normal epithelium (NE = 147 microm) over the different grades of epithelial dysplasia (EDI = 258 microm, EDII = 301 microm, CIS = 445 microm) to early invasive carcinoma (EIC = 974 microm), while benign lesions presented only a slight epithelial thickening of an additional 100 microm. In such a manner, moderate dysplasia showed a double increase, carcinoma in situ a triple increase and early invasive carcinoma even a sixfold increase of the mean epithelial thickness compared to normal laryngeal mucosa. As fluorescence inducing light has a penetration depth of approximately 300 microm, a marked loss of autofluorescence was recognized from moderate dysplasia onwards, while mild dysplasia simply revealed a slight loss of fluorescence. Autofluorescence microscopy demonstrated a threefold higher fluorescence intensity of the submucosal connective tissue compared to the epithelium, which showed always the same weak intensity independent of the grade of dysplasia. In most cases laryngeal epithelium demonstrates progressive thickening during cancer genesis leading to a loss of autofluorescence.

Laryngeal preneoplastic lesions and cancer: challenging diagnosis. Qualitative literature review and meta-analysis.

“…In regard to the diagnostic utility of WLE, Caffier et al (196) showed a higher accuracy for WL (97% vs. 81%) than AFE and AFE data analysis provided a reduction in specificity of 25% in comparison to WLS, together with a high false positive value (31%). These findings were in accordance with literature reports (197,198). On the other hand, even if Crosetti et al (199) confirmed that sensitivity and specificity of AFE in distinguish between benign and dysplastic/ neoplastic lesions are negatively impacted by different features (i.e.…”

“…In attention to avoid false positive and false negative findings, we recommended simultaneous careful comparison of white light and autofluorescent images of same view. Both effects: (1) epithelial thickening of (pre)malignant tissue with inhibited penetration of exciting light into submucous layers and (2) the altered metabolism of tumor cells with lower concentration of NADH and FAD, are claimed to be mainly responsible for the reduced total AF in neoplastic laryngeal tissue (197). These considerations are basic as far as concerns the application field of this method.…”

Fortschritte der endoskopischen Diagnostik von Dysplasien und Karzinomen des Larynx

“…Wir unterscheiden zwischen EBV, die sich in vertikale und horizontale sowie zelluläre Ausbreitungsdiagnostik differenzieren, wobei sich die konfokale Endomikroskopie (KOM) in 2 Gruppen einordnen ließe. [10].…”

Real-time thickness measurement of biological tissues using a microfabricated magnetically-driven lens actuator

“…For instance, the thickening of epithelium in the vocal folds is an indicator of early laryngeal cancer (Arens et al 2007). Another example is the measurement of the central corneal thickness that can be related to the intraocular pressure (IOP) to determine onset of glaucoma (Ehlers et al 1975).…”