Understanding of the normal structure of the bronchial wall is essential for analyzing abnormal findings in bronchoscopy. When an abnormal finding is found, the description of the morphological change according to the morphological classification is recommended, after which the changes in the existing structure should be evaluated. Such precise observation enables the localization of the main locus of each lesion in terms of the airway layer and estimation of the site of occurrence in the bronchial wall. This chapter describes the method of analyzing (stratified classification) abnormal findings in accordance with the Bronchoscopic Findings Classification (1) of the Japanese Society for Respiratory Endoscopy. Understanding the anatomy of the airway, especially the wall layer structure, is essential for performing high-quality bronchoscopy. Simultaneous recording of the spread and color of the lesion, presence of stenosis, type and degree of stenosis, coexistence of swelling, and shape (flat, polypoid or dented) is recommended when an abnormal finding in the airway is recognized. The main locus in the wall layer structure, site of origin, and mode of development should then be estimated, focusing on the changes in the existing structure in the bronchial lumen. The histological type and progression may also be predicted based on an understanding of the growth and progression pattern of each pathological type in cases of lung cancer. Findings of the abnormal lesions are summarized as morphological findings in the present revision, and observation items are defined. These observation items include the spread of the lesion (localized or non-localized), surface characteristics (color and tone), stricture, dilatation, shape (raised, flat [up to 2 mm in height], or dented), and other changes of the airway lumen. Next, the findings of abnormal lesions are further classified with regard to the bronchial wall layer structure, which includes the epithelium, subepithelial blood vessels, longitudinal folds, ring shape folds, and bronchial cricoid. After the classification of the abnormal findings according to the observation items, the main locus in the wall layer structure, site of origin, mode of development, and spread of the lesion can be understood. In this chapter, the method of analyzing abnormal findings using bronchoscopy in accordance with Revision of bronchoscopic findings classification is described (1).
