Haema 2017; 8(1): 74-82
by Dimitra Rontogianni1, Panagiota Giannoulia2, John Apostolidis2
1Department of Histopathology, 2Department of Hematology and Bone Marrow Transplantation, Evangelismos Hospital, Athens, Greece
Abstract
The 2016 revision of the WHO classification for lymphomas includes a new entity, separate from the other diffuse large B-cell lymphomas (DLBCL), termed High grade B-cell lymphoma with translocations of MYC and BCL2 and/or BCL6 (HGBCL-DH). These lymphomas account for less than 10% of cases of DLBCL, in the literature referred to as “double hit” or “triple hit” lymphomas. These cases must be distinguished from the larger group of “double expressor” (DE) DLBCL that account for 25-30% of cases, and which have increased immunohistochemical expression of MYC and BCL2 protein. HGBL-DH have a poor prognosis following conventional R-CHOP therapy, and have an increased risk of central nervous system involvement at presentation and at progression. There are no prospective studies for HGBL-DH in the literature, however retrospective studies suggest that outcome is improved when more intensified induction regimens are utilized. Patients are encouraged to enrol into clinical trials with novel targeted therapeutic agents. Patients with DLBCL-DE have better outcome than patients HGBL-DH but poorer when compared to non-DE. A recent phase 3 trial in patients with DLBCL comparing R-CHOP to DA-EPOCH-R failed to demonstrate a difference in outcome. As such, although an updated analysis comparing DE/non-DE is pending, and until further results are announced, patients with DLBCL-DE continue to be treated with standard R-CHOP or enrol into clinical trials.