INTRODUCTION: Fibrotic Hypersensitivity Pneumonitis (fHP) is often a diagnostic challenge. Clinical and radiological features do not always ensure a high confidence level diagnosis in multidisciplinary discussion (MDD), frequently resulting in lung biopsy.

OBJECTIVES: To assess the role of transbronchial lung cryobiopsy (TBLC) in the diagnosis of fHP.

METHODS: Retrospective study including patients submitted to TBLC diagnosed with fHP between 2014-2022 in our center.

RESULTS: Of 500 TBLC performed, fHP was diagnosed in 170 patients, 55,3% male, mean age 65,82±8,26 years. Most were former/active smokers (51,2%). fHP was clinically and/or radiologically suspected before TBLC in MDD in most patients (78,8%); the majority (85,3%) reported some form of environmental exposure. High-resolution computed tomography showed a UIP-like pattern in 54,7% of cases. Most patients had no functional impairment on either spirometry (mean FVC 87,9±14,7%) nor plethysmography (mean TLC 83,1±17,1%), but presented reduced diffusion capacity (mean DLCO 56,3±14,7%). Bronchoalveolar lavage lymphocytosis was absent in two-thirds (median lymphocyte proportion 14%). The median number of samples per patient was 4 (1;7), with a mean length of 5.5mm. Two lobes were biopsied in 45,3% of patients. The most frequent complication was pneumothorax (31,7%); 23,5% of patients required chest-tube drainage. The most frequent histopathological finding was airway-centered fibrosis with peribronchiolar metaplasia (86,5%). Only 5 patients proceeded with surgical biopsy after cryobiopsy and subsequent MDD.

CONCLUSION: TBLC proved to be a safe procedure with high yield, increasing the level of confidence for fHP in most cases presented in MDD.