Usefulness of endocytoscopy in evaluating transbronchial biopsy specimens.

Background: Endocytoscopy (ECS) provides a magnification of approximately 450× for real-time observation of lesion nuclei. Using ECS, we aimed to evaluate whether sufficient samples for diagnosis can be obtained during bronchoscopy. We also investigated whether ECS can enable two-class diagnosis of malignant or non-malignant transbronchial biopsy specimens in real-time during bronchoscopy.

Methods: This was a single-facility, prospective, observational, ex vivo study. Forty cases with localized peripheral pulmonary lesions underwent transbronchial biopsy with endobronchial ultrasonography using a guide sheath. Each biopsy specimen was immediately observed and evaluated endocytoscopically after the collection by the bronchoscopic procedure.

Results: Thirty-seven cases were enrolled. The diagnostic accuracy achieved by ECS was 91.9% (34/37). The agreement rate between the endocytoscopic evaluation and pathological diagnosis of each specimen (170 specimens) was 65.3% (111/170). The median time required for endocytoscopic evaluation per specimen was 70 s. When we judged a specimen to be malignant a second time on ECS evaluations of five specimens in one case, pathologically malignant specimens were collected in 26 of 27 cases (96.3%).

Conclusions: ECS with methylene blue staining may aid in the two-class diagnosis of malignant or non-malignant transbronchial biopsy specimens during bronchoscopy. This may reduce the number of tissue biopsies.