Figure 2.

Histopathology of the pituitary gland and lymph node in a patient with IgG4-related disease. (a) Hematoxylin and eosin staining of the pituitary gland (2010). Bar 100 μm. The gland structure was unclear, and numerous lymphocytes and plasma cells had infiltrated the fibrous tissue. (b) Immunohistochemical staining of the pituitary gland for IgG4 showed that IgG4-positive cells were sparse; they comprised about 10% of all IgG-positive cells. Bar 200 μm. (c) Hematoxylin and eosin staining of the lymph node (1994). Bar 100 μm. Plasma cell infiltration was abundant. (d) Immunohistochemical staining of the lymph node for IgG4 showed abundant IgG4-bearing plasma cells; they comprised over 50% of all IgG-positive cells. Bar 200 μm.