Background. PPLs are the current challenge in bronchoscopy. Recently, novel endoscopic approaches are developed, and guidance systems allows to reach PPLs better than few years ago. In literature, slim/thin bronchoscope (TB) presents a low diagnostic yield (DY) for PPLs.

Aim. To evaluate DY of TB for PPLs suspected for lung cancer non reachable with conventional bronchoscopy.

Methods. 176 patients with PPLs were evaluated from January 22 to December 22. 26 of them presented non reachable PPL with conventional bronchoscopy, and performed the procedure again with a TB under conscious sedation (4.1 mm outer diameter, 2.0 mm working channel - EB-710P, Fujifilm, Tokyo, Japan). Biopsies were performed with a 2.0 mm forceps. When possible, R-EBUS was used. PPLs dimensions at chest computed tomography (CT) were recorded. DY was evaluated.

Results. Mean lesion size was 30.4 mm, and overall DY was 65% (17/26). When lesion was bigger than 20 mm, DY was 75% (12/16), whereas in lesions smaller than 20 mm DY was 55% (5/9). When PPLs presented bronchus sign at CT scan, DY was substantially higher than PPLs without bronchus sign (12/15, 80% vs 5/11, 45%), independently form PPLs dimensions. R-EBUS did not change DY.

Conclusions. TB easily allows to reach and sample PPLs with a high DY if bronchus sign is positive, independently form PPLs dimensions. As for the newest guidance systems, if bronchus sign is absent, DY is substantially lower. Further studies are needed to evaluate if more flexible and penetrating bronchial wall biopsy tools can augment DY for PPLs.