Figure 3: (A-F): Eosinophilic angiocentric fibrosis form of IgG4RD. (3A): “Onion skin” perivascular fibrosis (asterix), 2x Hematoxylin & Eosin (HE) stain. (3B): HE stain, 40x. Marked eosinophil-rich (arrow) lymphoplasmacytic infiltrate. (3C): Masson Trichrome (MT) stain 4x. MT stain highlighting the perivascular fibrosis (asterix) and the background storiform fibrosis (arrowhead). (3D & E): CD138 and IgG4 immunohistochemistry (Peroxidase, 20x) showing increased tissue IgG4 CD138 positive plasma cells ~122 cell/ hpf. (3E & F): IgG4 and IgG immunohistochemistry (Peroxidase, 20x) showing increased IgG4: IgG ratio (80%).