[A case report of spinal epidural Ki-1 lymphoma presenting acute paraplegia without spinal cord compression at the first onset].

A 68-year-old man noticed weakness in both legs, which worsened rapidly with additional urinary disturbance. At the time of admission, a neurological examination revealed spastic paraplegia. Sensation was intact. Magnetic resonance imaging (MRI) did not show any lesions in the spinal cord. Thereafter, sensory disturbance under Th5 level and weakness in both hands developed gradually. Seven months after the onset, he noticed pain of the right upper arm. MRI showed an epidural mass at the level between the lower cervical and the upper thoracic spine. Histological examination of the epidural mass revealed Ki-1 lymphoma. In this case, the diagnosis was difficult, because lymphoma did not present epidural mass in the early stage. We speculate that spinal epidural lymphoma might disturb venous circulation and cause myelopathy in this patient.