Granulomatosis with polyangiitis (GPA) is a type of anti-neutrophil cytoplasmic antibody (ANCA) associated small vessel vasculitis that typically affects the kidneys, lungs and sinuses.1 Due to an overlap in signs and symptoms, GPA may initially be difficult to distinguish from IgG4-related disease, another condition that can affect multiple tissues and has variable presentations. Further complicating…
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