Abstract Background A definitive diagnosis based on histopathology is recommended for any form of ANCA-associated vasculitis (AAV)—including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA)—whenever feasible. Objective To identify clinical situations in which lung biopsy is useful for the diagnosis of AAV. Methods We retrospectively reviewed the medical records of patients who underwent lung biopsy for the histopathological diagnosis of AAV at St. Luke’s International Hospital (July 2003-August 2024) and at the National Center for Global Health and Medicine (January 2015-August 2024). Clinical, radiological, and pathological findings, as well as complications related to the procedure, were analyzed. Results A total of 31 patients clinically suspected of having AAV underwent bronchoscopic lung biopsy. These patients exhibited characteristic findings such as alveolar hemorrhage, serological ANCA positivity, and suspected vasculitic lesions involving extrapulmonary organs, including the nasal mucosa, kidneys, and skin. Of these, 4 cases (1 GPA, 1 EGPA, and 2 MPA) were histologically confirmed by transbronchial lung biopsy (TBLB). All of these cases demonstrated distinct pulmonary nodules, masses, or interstitial infiltrates attributable to AAV. Furthermore, 17 additional patients were ultimately diagnosed with AAV, although not through TBLB: 13 were diagnosed histologically from extrapulmonary tissues (nasal mucosa, skin, or kidneys), and 4 were diagnosed clinically. No biopsy-related complications, such as massive bleeding or pneumothorax, occurred among the patients who underwent TBLB. Conclusion Lung biopsy can be useful for the diagnosis of AAV, particularly in patients presenting with characteristic clinical features and evident pulmonary lesions. Careful patient selection may enhance diagnostic yield while minimizing procedural risks. This abstract is funded by: None
Sonoda et al. (Fri,) studied this question.