Fig. 2

Lymphoma biopsy. 1 Cells are composed predominantly of large lymphocytes two to three times larger than normal background small lymphocytes (Diff-Quik stain, × 100). 2 a–f Flow cytometry, left-sided neck mass: Flow cytometry of the left-sided neck mass shows a CD10 positive kappa light chain-restricted large B cell lymphoma with a background of small T cells and polytypic non-germinal center B cells. a Small T cells (green, 36% of cellularity) and small CD10 negative B cells (purple, 10%) with low forward scatter and large CD10 positive B cells (blue, 39%) with higher forward scatter. b CD5 positive T cells (green) and CD5 negative B cells (purple and blue). c CD10 positive B cells are larger by forward scatter than the T cells (green) and CD10 negative B cells (purple). d CD20 and CD10 positive large B cell lymphoma, germinal center type (blue) and CD10 negative B cells (purple). e CD10 positive B cells (blue) show clonal kappa light chain restriction. f CD10 negative B cells (purple) show polytypic light chain expression