PAX5 and Burkitt lymphoma: Figure 5 demonstrates a classic Burkitt's morphology encountered in an HIV patient with involvement of liver and right adrenal. The immunophenotype of HIV-BL is also similar to other Burkitt's lymphomas. Burkitt's lymphoma cells are LCA, CD20, CD79a, PAX5, CD10, BCL-6, and EBV positive and negative for BCL-2, CD3, CD5, CD21, CD23, CD43, cyclin D1, and TdT. HIV-BL also shows a virtually 100% Ki67 proliferation index. Studies have indicated that the plasmacytoid variant is most common in HIV-BL, often highlighted with CD138 staining [27].