www.jkns.or.kr http://dx.doi.org/10.3340/jkns.2012.52.2.156 J Korean Neurosurg Soc 52 : 156-158, 2012 Print ISSN 2005-3711 On-line ISSN 1598-7876 Copyright © 2012 The Korean Neurosurgical Society Case Report Intradural Migration of a Sequestrated Lumbar Disc Fragment Masquerading as a Spinal Intradural Tumor Hyeong-Suk Kim, M.D., Jong-Pil Eun, M.D., Ph.D., Jung-Soo Park, M.D. Department of Neurosurgery, Research Institute of Clinical Medicine, Institute for Medical Science, Chonbuk National University Medical School and Hospital, Jeonju, Korea Intervertebral intradural lumbar disc herniation (ILDH) is a quite rare pathology, and isolated intradural lumbar disc herniation is even more rare. Magnetic resonance imaging (MRI) may not be able to reveal ILDHs, especially if MRI findings show an intact lumbar disc annulus and posterior lon- gitudinal ligament. Here, we present an exceedingly rare case of an isolated IDLH that we initially misidentified as a spinal intradural tumor, in a 54-year-old man hospitalized with a 2-month history of back pain and right sciatica. Neurologic examination revealed a positive straight leg raise test on the right side, but he presented no other sensory, motor, or sphincter disturbances. A gadolinium-enhanced MRI revealed what we believed to be an intradural extramedullary tumor compressing the cauda equina leftward in the thecal sac, at the L2 vertebral level. The patient underwent total L2 laminectomy, and we extirpated the intradural mass under microscopic guidance. Histologic examination of the mass revealed a degenerat- ed nucleus pulposus. Key Words : Intradural disc herniation · Spinal intradural tumor · Magnetic resonance imaging. INTRODUCTION Intradural lumbar disc herniation (ILDH) is a rare condition, having a reported incidence of 0.04-0.33% of all lumbar disc herniations12,20). Since Dandy first described it in 19425), the oc- casional reports of ILDH have rarely described the condition at above the L2-3 level12,16,17). Moreover, only one case of intradural cranial migration of disc materials has been described18). Though ILDH can be diagnosed by means of magnetic reso- nance imaging (MRI), computed tomography (CT), and post- myelogram CT, such cases are rarely reported, due to physi- cians’ limited experience with this condition and its nonspecific presentation16). In addition, in cases having either intradural disc fragments that migrated upward or downward or no direct connection between the protruded disc materials and intradu- ral lesions, confusion with other spinal abnormalities, such as neurofibroma, lipoma, meningioma, epidermoid tumor, arach- noid cyst, or metastasis, may occur1,12). In this report, we present a case of a sequestrated lumbar disc fragment which is upward migration in intradural space at the L2 vertebra level mimicking an intradural extramedullary (IDEM) spinal tumor. CASE REPORT A 54-year-old man was admitted to the hospital after experi- encing pain in his lower back and right leg for the preceding 2 months. His symptoms included a sudden exacerbation of pain for the 2 days prior to his admission. Neurologic examination revealed a positive straight leg raise test on his right side, without sensory, motor, or sphincter disturbances. An MRI showed an intradural mass-like lesion at the L2 level vertebral body and ex- tending to the L2-L3 disc space, 10×23 mm in size, with degen- erative, diffuse disc bulging at all lumbar vertebral levels. This mass-like lesion had inhomogeneous signal intensity on a non- contrast MRI (Fig. 1). A gadolinium-enhanced MRI showed a partially-enhanced IDEM mass causing anterolateral compres- sion of the nerve roots in the thecal sac (Fig. 2). The patient un- derwent surgical removal of the L2 and L3 laminae. Upon ex- ploring carefully, we observed a swollen dural sheath, with • Received : January 5, 2012 • Revised : May 29, 2012 • Accepted : August 17, 2012 • Address for reprints : Jong-Pil Eun, M.D., Ph.D. Department of Neurosurgery, Chonbuk National University Medical School and Hospital, 20 Geonji-ro, Deokjin-gu, Jeonju 561-712, Korea Tel : +82-63-250-1870, Fax : +82-63-277-3273, E-mail : spineeun@chonbuk.ac.kr • This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 156