Fig. 1

a–o: Histomorphologic features and phenotypic profile of PBL cases. a & b H&E, PBL consists of a population of large lymphoid cells showing plasmablastic/immunoblastic morphology (a), cases 2 or plasmacytic morphology (b), case 7. c & d PBL typically lacks CD20 expression (c) and is strongly positive for CD138 (d), case 1. e Staining with Ki-67 shows a high proliferation rate, case 7. f & g Lambda, light chain shows positivity in neoplastic cells by immunohistological stain, case 4 and by ISH respectively, case 2. h & i Tumor cells show negativity to EBER in situ hybridization (h) and positivity to HHV8 by immunohistological stain (i) respectively, case 2. j and k PBL shows negativity to CD45, case 8 whereas shows strong and diffuse positivity in case 4 (k). l & m The tumor cells are positive for EMA (l), case 4 and positive for MUM-1 stain in case 7 (m). n & o Case 2 shows strong positivity for CD30 staining (n) and negative for ALK-1 immunohistochemical staining (o)