Durable remission in a patient with leptomeningeal relapse of a MYC/BCL6-positive double-hit DLBCL treated with lenalidomide monotherapy.

Secondary central nervous system involvement is an uncommon event that typically occurs early in the natural history of diffuse large B-cell lymphoma and presents as leptomeningeal dissemination in two-thirds of cases. The prognosis of this event is dismal, and treatment options are meagre. Although major validated risk factors for central nervous system dissemination are clinical, concomitant MYC/BCL2 rearrangements as well as MYC/BCL2 protein expression have been recently associated with an increased risk of this complication. Here we present the first case, to our knowledge, of a MYC/BCL6-positive double-hit diffuse large B-cell lymphoma relapsing in the leptomeninges that achieved an outstanding durable remission with single-agent lenalidomide following salvage chemotherapy.