Immunoglobulin G4-related lymph node disease with an orbital mass mimicking Castleman disease: A case report

Figure 2 Pathological morphology and immunohistochemistry of orbital mass. A: At low magnification, the histological morphology showed lymphoproliferative tissue, scattered lymphoproliferative follicles, and interstitial fibrous tissue proliferation (× 50); B: Histological morphology at high magnification showed hyperplasia of small vessels in the follicles, and a large number of plasma cells infiltrated between the follicles (× 200); C: CD38 immunohistochemical staining showed a large number of positive plasma cells in the interfollicular space; D: Immunohistochemical staining of CD138 showed a large number of positive plasma cells in the interfollicle; E: Immunoglobulin (Ig) G positive plasma cells could be seen by immunohistochemical staining; F: IgG4-positive plasma cells could be seen by immunohistochemical staining; The IgG4/IgG ratio was greater than 40%. HE: Hematoxylin and eosin stain; Ig: Immunoglobulin.