Intravascular large B-cell lymphoma (IVLBCL) is a subtype of B-cell lymphoma, characterized by lymphoma cell proliferation within small blood vessels. We herein describe a rare case with long spinal cord lesions caused by venous congestive myelopathy associated with IVLBCL. An 81-year-old man presented with paraplegia of the lower limbs and sensory disturbances. Magnetic resonance imaging revealed intramedullary longitudinal T2-hyperintensity lesions in the thoracic cords. The patient died three months after disease onset, and a neuropathological analysis revealed predominantly atypical B-lymphocytes located sparsely in the veins of the spinal cord. IVLBCL should be considered in the differential diagnoses of long spinal cord lesions.