Intravascular Large B-Cell Lymphoma Diagnosed by Open Brain Biopsy and Achievement of Remission After Early Initiation of Chemotherapy: Case Report

A 60-year-old man presented with progressive disturbance of consciousness. His father had died of malignant lymphoma, while his mother and sister died of acute leukemia. Magnetic resonance imaging (MRI) revealed multiple high-intensity lesions in the bilateral cerebral hemispheres on diffusion-weighted images. Serum soluble interleukin 2 receptor was 5,640 U/mL. Screenings of blood antibodies known to rise in autoimmune diseases were all normal. Cerebrospinal fluid examinations demonstrated slight elevation of protein and glucose, while the oligoclonal band and myelin basic protein were not elevated. Biopsies of bone marrow and random skin did not show any malignant features. His consciousness gradually deteriorated over a week, with lesions in his right frontal, left temporal, and bilateral parietal lobes shown to be growing. Therefore, open brain biopsy was performed, and one block of the right frontal lesion was harvested. Histological examination revealed atypical large cells only in the capillaries. Although immunohistochemical examinations showed positive staining for CD20, they were negative for CD3. Histopathological diagnosis was intravascular large B-cell lymphoma. After undergoing six cycles of intravenous chemotherapy with rituximab, cyclophosphamide, doxorubicin, and prednisone, his consciousness and neurological symptoms improved, and he appeared to achieve remission. Two years later, there have been no apparent recurrences, and the brain lesions have disappeared.