Background: Lymphoid neoplasm with 18q21.3/BCL2 and 8q24/MYC translocation to immunoglobulin (IG) genes as dual-hit lymphoma/leukemia is very rare and known to have a poor clinical outcome.
Design and methods: To clarify the clinicopathological characteristics of this malignancy, we analyzed 27 cases of cytogenetically proven dual-hit lymphoma/leukemia.
Results: Dual-hit lymphoma/leukemia was diagnosed at presentation in 22 cases and at relapse or disease progression in 5 cases. At the time of diagnosis of dual-hit lymphoma/leukemia, extranodal involvement was found in 25 cases (93%) and central nervous system involvement occurred in 15 cases (56%). The median survival and 1-year survival rate of the 27 cases were only 6 months and 22%, respectively, after diagnosis of the dual-hit lymphoma/leukemia. Seven cases of triple-hit lymphoma/leukemia (dual-hit lymphoma/leukemia with 3q27/BCL6 translocation) were included; the median survival of these patients was only 4 months from the diagnosis of the dual-hit lymphoma/leukemia. The duration of survival of the patients with a triple-hit malignancy was shorter than that of the other 20 cases of dual-hit lymphoma/leukemia (p=0.02). The translocation partner of MYC subdivided the dual-hit cases into two groups; 14 cases of IGH and 13 cases of IGK/L. The MIB-1 index was investigated in 14 cases with aggressive B-cell lymphoma, and was higher in the group with MYC-IGH translocation (n=7) than in the MYC-IGK/L group (n=7) (p=0.02). Overall survival was not different between the MYC-IGH translocation group (n=14) and the MYC-IGK or MYC-IGL translocation group (n=13).
Conclusions: Dual-hit lymphoma/leukemia is a rare but distinct mature B-cell neoplasm with an extremely poor prognosis characterized by frequent extranodal involvement and central nervous system progression with either of the translocation partners of MYC.