How fine needle aspiration cytology and flow cytometry helped in diagnosing a high-grade B-cell lymphoma masquerading as leukaemia.

High-grade B-cell lymphoma (HGBL) has recently been introduced into the category of aggressive, mature B-cell lymphomas. It is biologically different from diffuse large B-cell lymphoma and Burkitt lymphoma and exhibits an aggressive course. Leukaemic presentation, though known in various types of mature B-cell and mature T-cell lymphomas, is rare in high-grade B-cell lymphoma. We report one such case of a high-grade B-cell lymphoma which was masquerading as acute leukaemia with a soft tissue infiltration, with added emphasis on the role of fine needle aspiration cytology and flow cytometry in the diagnosis, and their therapeutic significance.