RT Journal Article SR Electronic T1 Lumbar extradural arachnoid cyst presenting as a conus lesion in a man aged 77 years. JF Journal of Neurology, Neurosurgery & Psychiatry JO J Neurol Neurosurg Psychiatry FD BMJ Publishing Group Ltd SP 126 DO 10.1136/jnnp.52.1.126 VO 52 IS 1 A1 J B Winer A1 A E Harding A1 L Symon A1 D P Kingsley YR 1989 UL http://jnnp.bmj.com/content/52/1/126.1.abstract AB