ACR 2022 Tweet by Dr. Antoni Chan

Doppelgängers are double walkers with similar features. GPA and IgG-RD are doppelgängers. 3 findings in GPA that are not found in IgG4-RD:

◦ Granulomatous inflammation
◦ Necrosis
◦ Neutrophilic infiltration

John Stone, Secrets and Pearls #ACR22 @RheumNow