Nasal biopsy in ANCA-associated vasculitis: a game changer or a false friend?

Ear-nose-throat (ENT) involvement is common in ANCA associated vasculitis, particularly in granulomatosis with polyangiitis (GPA) and EGPA eosinophilic granulomatosis with polyangiitis (EGPA), with sinonasal manifestations frequently representing the earliest clinical features of disease (1).