Double hit lymphoma - a case of unusual response after sequential aggressive chemotherapy and review of the literature.

Lymphomas with recurrent chromosomal breakpoints activating multiple oncogenes, including MYC, BCL2, and BCL6 are often referred to as "Dual Hit" or "Double Hit" lymphomas (DHL). In the updated classification for malignant lymphomas by the World Health Organization (WHO), the novel category of "B-cell lymphoma unclassifiable with features intermediate between diffuse large B-cell lymphoma (DLBCL) and Burkitt's lymphoma (BL)" was proposed in an attempt to create a (temporary) container for aggressive mature B-cell lymphomas that should not be diagnosed as either BL or DLBCL. DHL make up an important part of this novel WHO category, the other part representing heterogeneous cases of aggressive B-cell lymphoma that have features of BL. DHL are highly aggressive lymphomas with generally poor response to first line and salvage treatment. Limited data is available to guide therapeutic decisions, and despite aggressive measures including high dose (HD) chemotherapy followed by autologous hematopoietic cell transplantation (AHCT), outcome is unsatisfyingly poor. Herein, we report a case of a patient with DHL and review the relevant literature.