Figure 1
Morphologic features and proliferation index of plasmablastic lymphoma and plasmablastic plasma cell myeloma. (a) Plasmablastic lymphoma, case 6. Diffuse infiltrate of large cells, with a starry-sky pattern of tingible body macrophages (H&E, × 40). (b) Plasmablastic lymphoma, case 7. The tumor cells have features of immunoblasts; they are large with a vesicular chromatin and frequently prominent central nucleoli. Rare smaller neoplastic cells with plasmacytic differentiation are also noted (H&E, × 400). (c) Plasmablastic lymphoma, case 6. The proliferation index, as determined by Ki-67, was higher than 90% (Ki-67, × 400). (d) Plasmablastic plasma cell myeloma, case 1. Diffuse infiltrate characterized by a focal starry-sky background (H&E, original magnification × 40). (e) Plasmablastic plasma cell myeloma, case 1. The tumor cells have marked plasmacytic differentiation. Larger atypical cells with features of plasmablasts are interspersed among the plasmacytic cells (H&E, original magnification × 400). (f) Plasmablastic plasma cell myeloma, case 1. The proliferation index was higher than 90% (Ki-67, × 400).
