The diagnostic role of transbronchial lung cryobiopsy in vasculitis with pulmonary involvement

<bold>Background:</bold> Granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA) are systemic antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV), characterized by inflammation within small blood vessels, which can frequently involve the lungs. Histological confirmation is often required to obtain a diagnosis. Surgical lung biopsy (SLB) has a high diagnostic yield but is burdened by complications and requires hospitalization. Transbronchial lung cryobiopsy (TBLC) represent a less invasive option with fewer complications. <bold>Aim:</bold> to evaluate the diagnostic role, feasibility and safety TBLC in AAV. <bold>Methods:</bold> between 2014 and 2024, 10 cases of AAV underwent TBLC in our department. We retrospectively collected clinical, sierological and histological data. <bold>Results:</bold> Samples obtained by TBLC were all considered adequate, and histological features characteristic of AAV were found in 9 (90%) patients, comprising 6 cases of GPA, 2 EGPA, 1 MPA and 1 patient underwent surgical lung biopsy for confirmation of a drug-induced vasculitis. 4(40%) patients were female and 5(50%) were active or former smokers. ANCA were positive in 7(70%) patients, including 3 PR3-ANCA and 4 MPO-ANCA. Pneumothorax occurred in 2(20%) cases, but none of them required a chest tube placement. No patient experienced bleeding during the procedure. <bold>Conclusions:</bold> TBLC is a safe and minimally invasive approach for characterizing AAV, providing high diagnostic confidence and a low rate of complications.