Photomicrographs of Case 2. (a, b) High-power photomicrographs showing inflammatory cells infiltrating the pituitary tissue (a) and the dura mater (b). Hematoxylin and eosin staining, original magnification × 200. (c, d) Immunohistochemical staining showing infiltrated plasmacytes positive for IgG4 in the pituitary tissue (c) and the dura mater (d). Original magnification × 400.