Figure 3 Histopathologic findings of the right upper extremity wound biopsy.Hematoxylin and eosin staining at original magnification ×10 demonstrates lymphocytic vasculitis with transmural infiltration of the vessel wall (A), with similar findings confirmed at ×20 magnification (B). Immunohistochemical staining for cluster of differentiation 3 (CD3) at ×10 magnification highlights a background population of reactive T lymphocytes characteristic of lymphomatoid granulomatosis (C). Immunohistochemical staining for CD20 at ×20 magnification demonstrates neoplastic B lymphocytes infiltrating and destroying the vascular walls (D). Immunohistochemical staining for CD30 at ×20 magnification highlights tumor cells within vessel walls (E). Paired box gene 5 immunohistochemical staining at ×40 magnification confirms B-cell lineage of the neoplastic cells (F). Epstein-Barr virus–encoded RNA in situ hybridization at ×40 (G) and ×60 (H) magnification demonstrates strong positivity within the tumor cells, supporting a diagnosis of Epstein-Barr virus–associated lymphomatoid granulomatosis, grade 3.