Ultrathin bronchoscopy-guided small airway biopsy for diagnosing sarcoidosis: A prospective study

New ultrathin bronchoscopes (UTBs) enable the inspection and biopsy of small airways, potentially offering diagnostic advantages in sarcoidosis. In this prospective study, patients with suspected sarcoidosis underwent airway inspection with a UTB. Observed airway abnormalities were categorised into six predefined patterns. UTB-directed small airway biopsies (SABs) were collected from the upper lobes following a standardised procedure. We evaluated the prevalence and patterns of SAAs, as well as the diagnostic yield of UTB-directed SAB. Among 79 participants, 65 (82.3%) were diagnosed with sarcoidosis. Small airway abnormalities were identified in 26/65 (40%) patients, predominantly in those with parenchymal involvement on CT compared to those with lymphadenopathy only (58.1% VS. 23.5%, P = 0.005). The diagnostic yield of SABs for detecting granulomas was significantly higher in patients with SAAs than in those without (65.4% VS. 23.1%, P = 0.001) and in patients with parenchymal disease on CT compared to those without (54.8% VS. 26.5%, P = 0.02). Notably, random biopsies taken under direct visualisation from small airway carinas revealed peribronchiolar parenchyma in 23% of the patients. Small airway abnormalities are prevalent in sarcoidosis patients with parenchymal involvement, and biopsying these abnormalities yields a high rate of granuloma detection.