Fig. 2

The tissue or bone marrow involvement pattern and immunophenotypic profiling of the EMWM and BMWM patients. a, b A representative diffuse interstitial pattern of bone marrow biopsy in a patient with BMWM, ×40 and × 80 magnification. c Bone marrow aspirate smear showed many abnormal small lymphoid cells admixed with variable plasmacytoid cells and plasma cells, ×80 magnification. d CD20 stain on the abnormal small lymphoid cells, ×80 magnification. e CD138 stain on the plasmacytoid and plasma cells, ×80 magnification. f, g Immunophenotypic profiling of CD38 and CD138 positive plasmacytoid and plasma cells with strong monotypic cytoplasmic kappa light chain expression. h The abnormal small lymphoid cells were CD20 positive and showed monotypic kappa light chain expression. i, j A representative diffuse infiltrative pattern of a lymph node biopsy in a patient with EMWM, MYD88 mutation positive, ×40 and × 80 magnification. k CD20 stain on abnormal small lymphoid cells, ×80 magnification. l CD138 stain on few admixed plasmacytoid and plasma cells, ×80 magnification. m, o Immunophenotypic profiling of CD19 and CD20 positive small B-cells with kappa light chain restriction and were negative for CD5 and CD10. p Identical monotypic kappa light chain expression in the lymphoid cells was also seen in the plasmacytoid and plasma cells