Clonally related transformation from Waldenström macroglobulinemia to diffuse large B-cell lymphoma with central nervous system involvement at diagnosis: a case report and literature review.

Histological transformation to diffuse large B-cell lymphoma (DLBCL) rarely occurs in patients with Waldenström macroglobulinemia (WM). The median time from WM diagnosis to DLBCL is 4-5 years. Extranodal involvement is common in transformed WM. However, central nervous system (CNS) involvement is relatively uncommon. Here, we report a case of a simultaneous diagnosis of WM and clonally related DLBCL, with the involvement of CNS demonstrated by dual enhancement in MRI. Nevertheless, it is unclear if CNS infiltration is caused by DLBCL or WM for the inaccessibility of brain biopsy. Intensified chemotherapy and Bruton tyrosine kinase inhibitor were administrated, and a good response was achieved.Please check the edit made in the article title.we have checked it.