The Usefulness of a Simple Classification for Bronchoscopic Findings for Diagnosis of Peripheral Pulmonary Tumour

Abstract

<b><i>Background:</i></b> Normal bronchial epithelium has been described in terms of transparency and smoothness. No studies have compared bronchoscopic and pathological findings in the identification of bronchial epithelium. <b><i>Objectives:</i></b> This study aimed to classify bronchoscopic findings for peripheral pulmonary tumour (PPT) for accurate bronchoscopic diagnosis accounting for the presences of bronchial epithelium and bronchial stenosis using an ultrathin bronchoscope. <b><i>Methods:</i></b> We performed endocytoscopy using narrow-band imaging (NBI) of specimens immediately after lobectomy to investigate the normal bronchial epithelium under the physiological saline injection technique (PSIT) prior to classification of PPT. A retrospective study to classify bronchoscopic findings included 46 patients diagnosed with malignancy by bronchoscopy for PPT. <b><i>Results:</i></b> We recognized a “light blue line” (LBL) with NBI under PSIT, corresponding to strong reflection of short-wavelength light by cilia on the epithelial surface in an ex vivo endocytoscopic study. Bronchoscopic findings of PPT were classified morphologically into stenotic type (ST) and non-stenotic type (NonST). Tumours were also classified as exposed type (ET) and non-exposed type (NonET) based on the presence of epithelium. Most ST and NonET lesions (74%) were adenocarcinoma. Among squamous cell carcinoma, 55% were categorized as ST and ET. All NonST and NonET cases were adenocarcinoma. A significant difference in the presence of LBL was seen between ET and NonET. <b><i>Conclusions:</i></b> Our simple classification based on the appearance of stenosis and LBL in PPT may facilitate pathological diagnosis.

A narrative review: narrow-band imaging endoscopic classifications

“…In 2021, Fukada et al proposed a simple system to classify the bronchoscopic images of peripheral pulmonary tumor (PPT) ( 129 ). Based on the appearance of stenosis, the lesions were divided into stenotic type (ST) and non-stenotic type (NonST).…”

Bronchoscopic Diagnosis of Peripheral Lung Lesions

“…The bronchoscopy-pathology correlation study by Fukada and colleagues [13] reported in this issue provides an explanation as to why tissue sampling after arrival at the target lesion with confirmation by R-EBUS may not yield a diagnosis. The investigators used a physiological saline injection technique to dilate the small peripheral airways, leading the tumor to allow clearer observation of the endo-luminal features and then classified them into a stenotic or nonstenotic type and to determine if the tumor was exposed on the surface or submucosal with an intact ciliated epithelium as reflected by a light blue line using narrow band imaging.…”

“…The findings of the study by Fukada and colleagues [13] have practical implications. The use of ultrathin bronchoscopes and injection of physiological saline to dilate the small peripheral airways leading the tumor to allow clearer observation of the endo-luminal features to position forceps or TBNA needles for tissue sampling should lead to a higher diagnostic yield of small peripheral tumors [17].…”