Figure 2.
Histologic features of left medial rectus muscle biopsy. Hematoxylin and eosin stain at low (10x magnification) (left) and high power (40× magnification) (middle) demonstrates a perivascular mixed inflammatory infiltrate and venulitis without obliteration. IgG4 immunohistochemical stain (right) demonstrates plasma cells with strong IgG4 expression.