MME and neoplasm: Immunohistochemically, the tumor cells were positive for CD5 (Figure 2A), CD20 (Figure 2B), CD43, CD45, CD79α, bcl-2, and κ-chain (Figure 2C), but negative for λ-chain (Figure 2D), CD2, CD3 (Figure 2E), CD10, CD21, CD23, CD35, CD45RO, CD56, TdT, IgA, IgG, IgM, IgD, and cyclin D1.