Probe-based optical fiberscopy for the direct observation of peripheral pulmonary lesions

Abstract Background Peripheral pulmonary lesions are rarely observed directly before transbronchial biopsy. This study aimed to characterize the differences between malignant and benign peripheral pulmonary lesions according to the findings of direct observation using probe-based optical fiberscopy. Methods Thirty patients who underwent probe-based optical fiberscopy in combination with bronchoscopy using endobronchial ultrasonography with a guide sheath for the evaluation of peripheral pulmonary lesions were prospectively included in this study. The patients were divided into the malignant and benign groups according to their final diagnosis. The findings of probe-based optical fiberscopy in the two groups were compared. Results The numbers of patients who were diagnosed using histological or bacteriological analyses via bronchoscopic sampling in the malignant and benign groups were 20/23 (87.0%) and 2/7 (28.6%), respectively. On probe-based optical fiberscopy, angiogenesis and vascular engorgement were observed only in the malignant group. The disappearance of subepithelial microvessel transparency and presence of bronchiolar stenosis were observed more frequently in the malignant group (78.3% and 60.9%) than in the benign group (28.6% and 28.6%), whereas increased mucus secretion was observed more frequently in the benign group (71.4%) than in the malignant group (8.7%). Conclusions These results suggest that the findings of direct observation using probe-based optical fiberscopy are useful for differentiating malignant from benign peripheral pulmonary lesions. Trial registry UMIN-CTR; UMIN000018796; URL: https://www.umin.ac.jp/ctr/index.htm .