Staging bone marrow in diffuse large B-cell lymphoma: the role of ancillary investigations

Diffuse large B-cell lymphoma DLBCL is an aggressive non-Hodgkin's lymphoma NHL that requires treatment at initial diagnosis. Treatment decisions may be guided by staging investigations, which include assessment of bone marrow BM. Traditionally this assessment has included light microscopic examination of the bone marrow aspirate and trephine biopsy. Ancillary testingincluding immunophenotyping using flow cytometry on BM aspirates, immunohistochemistry IHC on BM trephines and molecular studies using immunoglobulin heavy IgH or light IgL chain gene rearrangementsare performed as required to aid histological diagnosis. This review examines the evidence for the routine use of ancillary tests in the initial staging of DLBCL, including the limitations, potential pitfalls and possible clinical implications of their use in this setting