What is Double-hit lymphoma?
Double-hit lymphoma meaning A rare non-Hodgkin lymphoma subtype that is usually associated with a poor prognosis. Double-hit lymphomas have morphologic, phenotypic, and genetic features intermediate between DLBCL and BL. However, the characteristic cytogenetic abnormalities involve chromosomal rearrangements of c-MYC and BCL-2. The clinical implication of correctly diagnosing this entity is significant, as double-hit lymphomas also have a much worse prognosis than either DLBCL or BL alone, and therapeutic options are different. In comparison to double hit lymphomas, triple hit lymphoma posses three gene rearrangements: c-MYC, BCL-2 and BCL-6. Double hit lymphomas only have the c-MYC and BCL-2. They are associated with a much more aggressive clinical course. These lymphoma have a propensity to spread to extranodal sites, including the bone marrow and central nervous system. Because of the more complicated clinical course and gene rearrangements, the standard chemotherapy used for DLBCL or BL is ineffective. The survival rate for these lymphomas has been reported to be about 4 months, shorter than for DLBCL, BL, and double hit lymphomas. One of the challenges is to recognize these lymphomas and order the appropriate molecular studies so that aggressive treatment may be started.