A 62-year-old man complained of gait disturbance, bladder and bowel dysfunction and paresthesia of both legs one month before admission. His symptoms were suggestive of cauda equina syndrome. After admission, he developed rapid progressive numbness and weakness of both legs and a disturbance of consciousness. A random skin biopsy was performed and a histological diagnosis of intravascular large B cell lymphoma (IVLBCL) was reached. His symptoms were improved after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy.