Early relapse in a case of primary bone marrow diffuse large B-cell lymphoma treated with rituximab-CHOP.

As an uncommon disease, primary bone marrow diffuse large B-cell lymphoma (PBM DLBCL) is rarely reported in recent years. In this paper, we discuss a case of a 58-year-old man who presented with fever and fatigue, and was diagnosed with PBM DLBCL. Although the initial diagnosis reflected a positive expression of CD20 by lymphoma cells, the course of disease appeared as a rapid remission but a quick recurrence, after eight cycles of rituximab-based immunochemotherapy (R-CHOP). With the positive expression of CD20 in recurrent lesions, he received another four cycles of rituximab-based immunochemotherapy (R-GDP). However, an earlier relapse still occurred, and he died of CNS involvement. PBM DLBCL has been classified as an aggressive type of DLBCL, which should be heavily treated since the initial diagnosis. MYC-BCL2 gene rearrangement and P53 gene mutation cannot be ignored. Of note, rituximab resistance has become a severe and urgent problem in the rituximab era.