[Case of intravascular large B-cell lymphoma (IVLBCL) with central nervous system symptoms diagnosed by renal biopsy].

A 60-year-old man was admitted to our hospital complaining of fever, headache and vertigo. Neurological examination on admission showed mild ataxic gait. Brain magnetic resonance imaging showed linear high intensity in the left parietal lobe on diffusion-weighted imaging (DWI) and laboratory data revealed elevated serum lactate dehydrogenase and soluble interleukin-2 receptor. Although intravascular lymphoma was suspected from these findings, bone marrow and skin biopsies were negative. Two months later, he presented with sensory disturbance of the left upper limb, and new lesions in the right frontal and bilateral parietal lobes were detected on DWI. A systemic evaluation showed multiple low-density lesions in the bilateral kidneys on computed tomography. Based on the results of a renal biopsy, we made a histological diagnosis of intravascular large B-cell lymphoma (IVLBCL). As IVLBCL is quite rare and often has a poor prognosis, a systemic evaluation to determine the proper biopsy site is needed for early diagnosis.