Secondly, the patient had developed THRLBCL with or without the influence of methotrexate, which caused multiple extranodal and nodal lesions. The location and the timing of the biopsy could have complicated the results of the CNS pathology. We selected a lesion in the right thalamus for biopsy, while the largest mass was located in the cerebellum. Furthermore, the brain biopsy was performed after two courses of high-dose corticosteroid administration because we expected that steroid therapy would prevent disease progression. Considering the fact that corticosteroids were not administered prior to the biopsies of the non-CNS lesion and that atypical B-cells were not detected in these specimens, this interpretation is less likely.