Figure 3.

Primary central nervous system lymphoma (diffuse large B-cell lymphoma). (A) Angiocentric pattern of distribution of atypical lymphoid cells (original magnification ×100); (B) Atypical lymphoid cells are large with irregular nuclei and scant cytoplasm (original magnification ×400); (C) Tumor cells are diffusely positive for CD20 (original magnification ×100) and (D) usually show a high Ki-67 proliferation index (original magnification ×100); (E) Tumor cells are positive for BCL 2 (original magnification ×100); (F) Tumor cells are positive for MUM-1 (original magnification ×100). PCR analysis of B-cell monoclonal immunoglobulin heavy chain gene rearrangement detected monoclonal rearrangement of IGH FR2-JH (G) and IGK Vκ-Jκ (H).