Transbronchial lung cryobiopsy (TBLC) is increasingly used to diagnose interstitial lung disease; however, its diagnostic accuracy for fibrotic hypersensitivity pneumonitis (HP) remains uncertain. We aimed to compare disease progression between patients with fibrotic HP diagnosed by TBLC-based multidisciplinary discussion (TBLC-MDD) and those diagnosed by surgical lung biopsy-based MDD (SLB-MDD). This single-center retrospective study included patients diagnosed with fibrotic HP via MDD between January 2005 and June 2023. Histopathological findings—chronic fibrosing interstitial pneumonia, airway-centered fibrosis, and poorly formed nonnecrotizing granulomas—were assessed using the 2020 ATS/JRS/ALAT HP guidelines. For SLB-MDD patients who underwent TBLC prior to SLB, changes in diagnostic confidence were evaluated. To compare overall survival (OS) between the TBLC-MDD and SLB-MDD groups, 1:1 propensity score matching was performed. OS was analyzed using the Kaplan–Meier method and Cox proportional hazards models. Histopathological features were significantly less prevalent in TBLC than in SLB specimens. In the first lower-lobe specimen, chronic fibrosing interstitial pneumonia was identified in 26% of TBLC compared to 89% of SLB specimens ( p < 0.001). Among 31 SLB-MDD patients with prior TBLC, SLB significantly improved diagnostic confidence in 26 patients (84%; p < 0.001). After propensity score matching (96 pairs), TBLC-MDD patients showed significantly better OS than SLB-MDD patients (HR, 0.436; 95% CI, 0.197–0.963; p = 0.035). Within the TBLC-MDD group, concordance for chronic fibrosing interstitial pneumonia between the first and second lower-lobe specimens was poor (κ = 0.092). The presence of chronic fibrosing interstitial pneumonia in the second lower-lobe specimen independently predicted mortality (HR, 3.233; 95% CI, 1.115–9.376; p = 0.031), whereas findings from the first lower-lobe specimen were not statistically significant. Patients with fibrotic HP diagnosed by TBLC-MDD exhibited a more favorable prognosis than those diagnosed by SLB-MDD, likely due to insufficient subpleural sampling by TBLC. TBLC should be considered a complementary diagnostic tool to SLB for fibrotic HP, and its interpretative limitations might be carefully addressed during MDD.
Okuma et al. (Tue,) studied this question.