Case Reports / Journal of Clinical Neuroscience 19 (2012) 617–619 617 Insights on the natural history and pathogenesis of multilevel discal cysts Artid Lame, Gentian Kaloshi ⇑, Artur Xhumari, Gjergj Vreto, Mentor Petrela Department of Neurosurgery, Tirana School of Medicine, University Hospital Center ‘‘Mother Theresa’’, 327 Rr e Dibres, Tirana 99, Albania a r t i c l e i n f o Article history: Received 9 March 2011 Accepted 30 May 2011 Keywords: Discal cysts MRI Multilevel discal cyst Natural history a b s t r a c t Discal cysts are rare lesions and uncommon causes of low back pain and radiculopathy. Despite growing evidence regarding the clinical, pathological and radiological presentation of these lesions, we do not yet have a detailed understanding of their natural history, etiology or pathogenesis. To our knowledge this is the first report of multiple and multilevel discal cysts, and possible mechanisms of pathogenesis are proposed. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Extradural cysts occur frequently in the lumbar spine and the differential diagnosis includes synovial cysts of the lumbar facets, cysts of the ligamentum flavum, arachnoid cysts, enteric or dermoid cysts, cystic neurofibromas, ganglion cysts and discal cysts.1,2 The last, also known as disc cysts, are rare lesions defined as extradural cysts with distinct communication with the corresponding intervertebral disc.1 Despite growing evidence regarding the clinical, pathological and radiological presentation of these lesions, we do not yet have a detailed understanding of their natural history, etiology or pathogenesis. To our knowledge this is the first report of multilevel discal cysts in a young male adult and the natural history and possible mechanisms of pathogenesis are discussed. 2. Case report A 32-year-old male patient, who had worked as a chef for 10 years prior, presented at our department with moderate low back pain, which had been present for 5 years. Two months before hospitalization, he experienced his first episode of right-sided sciatica, which resolved spontaneously. After one month, he complained of progressively worsening pain and numbness radiating from the right buttock to the antero-lateral thigh. From his medical history, we noted that he had been in a car accident one year before hospitalization. The neurological examination revealed a limited range of motion of the lumbar spine and marked paravertebral muscle spasm in the lower lumbar spine. The straight-leg raise test was positive on the right at 30 degrees. The right patellar reflex was hypoactive. Sensory examination demonstrated diminished pinprick sensation in the right L4 dermatome. No other sensory, motor, or sphincter disturbance was noted. Although there was minimal neurological deficit, the pain affected his everyday life as well as his work. An MRI scan demonstrated an extradural 10 mm by 19 mm cystic lesion in the right ventrolateral space of the spinal canal immediately behind the L4 vertebral body. A cyst stalk indicated communication of this lesion with the fibrous capsule of the L3– L4 intervertebral disc. The cystic mass displaced the thecal sac and right L4 nerve root dorsally. There was also a small cystic spherical lesion in close contact with the annulus fibrosus (AF) of ⇑ Corresponding author. Tel: +35542362641. E-mail address: g_kaloshi@yahoo.com (G. Kaloshi). the L4–L5 intervertebral disc. These cystic lesions were hypointense on T1-weighted MRI and hyperintense on T2-weighted MRI, on both sagittal and axial views (Figs. 1 and 2). Mild degeneration (signal alteration compatible with nucleus pulposis dehydration) of both the L3–L4 and L4–L5 intervertebral discs was noted. In addition, bony erosion of the L4 vertebral body was present. The patient underwent surgery; a dark red cyst was visualized through an L3–L4 fenestration over the ventrolateral aspect of the thecal sac adjacent to the cephalic portion of the L4 vertebral body, and then aspirated. The cyst contained bloody serous fluid. Despite the apparent connection between the corresponding disc and the cyst, we did not perform a discectomy because the intervertebral disc did not appear to compress the nerve root. No complication was observed. After surgery, immediate and complete pain relief was noted. To elucidate the natural history of such cystic discal lesions, an MRI of the lumbar spine was performed at 10 months postoperative. This demonstrated the cyst at the L4–L5 intervertebral disc level; which had not changed in size. An obvious communication with the intervertebral disc was still present. No recurrence of the cyst excised at the L3–L4 level was evident. 3. Discussion Discal cysts, also known as disc cysts, are a newly recognized entity. They are rare lesions defined as extradural cysts with a distinct communication with the corresponding intervertebral disc. However, they are not necessarily associated with extensive degenerative disease of the adjacent lumbar disc.1 Their radiological characteristics, including ventral location, intimate or pedicled attachment to the annulus fibrosus, and absence of connection with a degenerative facet joint, help distinguish discal cysts from other extradural cysts of the lumbar spine. However, discal cysts show similar epidemiological, clinical, radiological and pathological features to ganglion cysts. Therefore the distinction based on disc–cyst communication does not seem to be important.3 To the best of the authors’ knowledge, we present the first report of multilevel discal cysts in a young adult man. Most discal cysts are reported in male patients in their early 30s. Our patient presented with a long history of low back pain. These findings support the hypothesis of a particular mechanical stress-induced focal degeneration of the annulus fibrosus and fluid collection in this young male due to repetitive trauma, physical activity and/or hormonal influence. Although the literature offers a number of different clinical, pathological and radiological presentations of discal cysts, we still 618 Case Reports / Journal of Clinical Neuroscience 19 (2012) 617–619 Fig. 1. Preoperative (a–c) sagittal (a, b) T2-weighted and (c) T1-weighted MRI showing a cystic mass below the L3–L4 intervertebral disc (arrows): a second cystic lesion is evident at the L4–L5 level (arrows). The cystic mass shows homogeneous isointensity to the cerebrospinal fluid. (d) T2-weighted axial MRI at L3–L4 and (e) T1-weighted axial MRI with gadolinium at L4–L5 show the large cyst extending downward and compressing the L4 nerve root on the right side and the smaller cyst at the L4-L5 level. Communication of the cyst with the adjacent intervertebral disc is evident. Fig. 2. Postoperative MRI obtained 10 months after surgery showing (a) sagittal T2-weighted MRI confirming the absence of residual/recurrent cystic mass in the L3–L4 intervertebral disc and the presence of the unchanged second cystic lesion at the L4–L5 level. (b, c) axial T2-weighted MRI at (b) the L3–L4 and (c) L4–L5 levels, respectively. lack clear information on their pathophysiology and natural history. Several hypotheses on mechanisms of pathogenesis have been proposed.1,4 In our patient, cysts at L3-L4 and L4-L5 showed evi- dent communication with the annulus fibrosus. For that reason, discography was thought to be unnecessary. Therefore, the bloody content of our excised cyst cannot be of iatrogenic origin, as some authors have previously speculated.1 A possible explanation for the Case Reports / Journal of Clinical Neuroscience 19 (2012) 617–619 cyst development and its bloody contents is impaired resorption of an epidural hematoma resulting from hemorrhage of the epidural venous plexus caused by either disc herniation or an underlying disc injury.1 However, if that was the case, the impairment would be continuing and the cyst growing. This was not the case. The second and non-treated cyst did not change in size over a follow-up of 10 months. What created the cyst and its bloody contents? It is well known that the blood vessels of the longitudinal ligaments reach into the outer annulus fibrosus.5 This is seen not only in fetal and juvenile disc samples, but also in adolescent and young adult discs, regardless of age. These findings support the existence of differences in the age-associated extension of blood vessels into the outer annulus fibrosus, compatible with the overwhelming predominance of young adults with discal cysts. This vascular in-growth into the intervertebral discs in the context of disc herniation has been reported in several papers and appears to be a consistent finding.6 In our opinion, it is this vascular network playing the major role in resorption of the herniated and/or degenerated disk material and consequently in the development of a disc cyst and intracystic hemorrhage. Despite some isolated case reports on (not strictly) spontaneous discal cyst regression,2 their natural history remains unknown. Bedoi:10.1016/j.jocn.2011.05.037 619 cause our second cyst did not change, we believe that the pathological mechanism is a trauma-induced step-by-step process. Our last observation is that decompression of the cyst contents and subsequent resection of the cyst stalk was sufficient to prevent recurrence. However, longer follow-up is needed to better evaluate this approach. References 1. Chiba K, Toyama Y, Matsumoto M, et al. Intraspinal cyst communicating with the intervertebral disc in the lumbar spine. Spine 2001;26:2112–8. 2. Chou D, Smith JS, Chin CT. Spontaneous regression of a discal cyst. J Neurosurg Spine 2007;6:81–4. 3. Marshman LA, Benjamin JC, David KM, et al. ‘‘Disc cysts’’ and ‘‘posterior longitudinal ganglion cysts’’: synonymous entities? Report of three cases and literature review. Neurosurgery 2005;57:818. 4. Kono K, Nakamura H, Inoue Y, et al. Intraspinal extradural cysts communicating with adjacent herniated disks: imaging characteristics and possible pathogenesis. Am J Neuroradiol 1999;20:1373–7. 5. Nerlich AG, Schaaf R, Walchli B, et al. Temporo-spatial distribution of blood vessels in human lumbar intervertebral discs. Eur Spine J 2007;16:547–55. 6. Repanti M, Korovessis PG, Stamatakis MV, et al. Evolution of disc degeneration in lumbar spine: a comparative histological study between herniated and postmortem retrieved disc specimens. J Spinal Disord 1998;11:41–5.