Intrinsic spinal cord lesions in 2 patients with ankylosing spondylitis

Two men with longstanding ankylosing spondylitis (AS) developed spastic paraparesis. Extensive investigation failed to find a cause and it was concluded that some acute undetermined intrinsic spinal cord lesion had occurred. Similar descriptions in the past have been attributed to associated multiple sclerosis, but we suggest that the finding may represent a rare complication of AS with an unknown etiology.