Lumbar Discal Cyst
An 18-year-old male student presented with complaints of low back pain and left thigh pain for more than one year. Despite nonsurgical treatment for longer than 6 months, the pain persisted.
Examination revealed mild paraspinal muscle spasm and bilateral straight leg raise of 80-degrees with mild restriction of spine movement.
Nonsteroidal anti-inflammatory drugs and physiotherapy
Radiographic studies of the lumbosacral spine demonstrated disc degeneration at L5-S1.
Figure 1A. Sagittal MRI, L1-L5
Figure 1B. Axial MRI, L2-L3
Figures 2A and 2B (below) are postdiscography.
Figure 2A. Sagittal MRI, L1-L5
Figure 2B. Axial MRI, L2-L3
Discal cyst at L2-L3
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A selective nerve root block determined that the L2 nerve root was causing leg pain. The patient was scheduled for percutaneous transforaminal endoscopic discectomy at L2-L3.
Prior to the endoscopic discectomy, discography with contrast (Iohexol) was performed. Discography was positive for severe neuralgic pain from the L2 root. Further, a circular shadow, expanding with the contrast injection, was seen in the epidural space in the C-arm image. Because of the severity of the patient's pain, the procedure was aborted and a repeat MRI was performed.
The MRI revealed a hypo-intense mass surrounded by bright rim on the injection side in connection with the L2-L3 disc and in close association with the affected nerve root. The diagnosis of discal cyst was confirmed.
A laminotomy was performed and the cyst's wall fully removed. Discectomy was not done as the nerve root was freely mobile after the cyst excision.
Figure 3A. Postoperative posterior anterior x-ray
Figure 3B. Postoperative lateral x-ray
He had complete pain relief postoperatively which status he enjoys till now, 15 months after the surgery. He had postoperative weakness (grade 4) of the left quadriceps, which recovered by 3 months.
Discal cysts are a rare disorder of the spine which are seldom reported and only recently gaining clinical exposure. The literature on discal cysts is limited to select case reports and small series with the earliest confirmed reports from 2001. (1) Increased awareness and rising clinical suspicion are likely the explanation for a rising number of case reports, particularly over the last two years.
Most of the reported cases in the literature are young men who present with focal lumbosacral radiculopathies. (1-8) Magnetic resonance imaging (MRI) typically reveals discal cysts as an intraspinal extradural mass with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. (9) The lesions typically have a ring-enhancing pattern after contrast administration.
Discography often reveals the continuity of the disc space with the cyst lumen. In this case, the postdiscography contrast and clinical reproduction of symptoms lead to the diagnosis.
The cysts are thought to arise from resorption of herniated discs, mucoid degeneration or hematomas in the epidural plexus from disc collapse. (1) In the later case, the osmotic gradient driving fluid into the cyst is thought to be responsible for cyst enlargement. Resected cysts typically demonstrate fibrous connective tissue without a synovial or endothelial lining on histology. (1, 8)
Treatment options typically include endoscopic resection (2, 3, 10), laminotomy (4, 5, 11, 12), steroid injection (6), CT-guided aspiration (7), or a combination (13). However, one author reported spontaneous resorption of the cyst after selective nerve root blocks (14).
Diagnosis of discal cysts relies on the clinician awareness and suspicion. While most cases reported arise from Asian centers, it is too early to say whether incidence is any lower in non-Asian continents.
1. Chiba K, Toyama Y, Matsumoto M, Maruiwa H, Watanabe M, Nishizawa T. Intraspinal cyst communicating with the intervertebral disc in the lumbar spine: discal cyst. Spine 26: 2112-2118, 2001.
2. Kim JS, Choi G, Lee CD, Lee SH. Removal of discal cyst using percutaneous working channel endoscope via transforaminal route. Eur Spine J. 2009 Jul; 18 Suppl 2:201-5. Epub 2008 Nov 26.
3. Kim JS, Choi G, Jin SR, Lee SH. Removal of a discal cyst using a percutaneous endoscopic interlaminar approach: a case report. Photomed Laser Surg. 2009 Apr; 27(2):365-9.
4. Hwang JH, Park IS, Kang DH, Jung JM. Discal cyst of the lumbar spine. J Korean Neurosurg Soc. 2008 Oct; 44(4):262-4. Epub 2008 Oct 30.
5. Marushima A, Uemura K, Sato N, Maruno T, Matsumura A. Osteolytic lumbar discal cyst: case report. Neurol Med Chir (Tokyo). 2008 Aug; 48(8):363-6.
6. Dumay-Levesque T, Souteyrand AC, Michel JL. Steroid injection performed with fluoroscopy for treatment of a discal cyst. J Rheumatol. 2009 Aug; 36(8):1841-3.
7. Kang H, Liu WC, Lee SH, Paeng SS. Midterm results of percutaneous CT-guided aspiration of symptomatic lumbar discal cysts. AJR Am J Roentgenol. 2008 May; 190(5):W310-4.
8. Murata K, Ikenaga M, Tanaka C, Kanoe H, Okuaaira S. Discal cysts of the lumbar spine: a case report. J Orthop Surg (Hong Kong). 2007 Dec; 15(3):376-9.
9. Lee HK, Lee DH, Choi CG, Kim SJ, Suh DC, Kahng SK, Roh SW, Rhim SC. Discal cyst of the lumbar spine: MR imaging features. Clin Imaging. 2006 Sep-Oct; 30(5):326-30.
10. Ishii K, Matsumoto M, Watanabe K, Nakamura M, Chiba K, Toyama Y. Endoscopic resection of cystic lesions in the lumbar spinal canal: a report of two cases. Minim Invasive Neurosurg. 2005 Aug; 48(4):240-3.
11. Marshman LA. Discal cysts. J Neurosurg Spine. 2007 Nov; 7(5):575-6; author reply 576-7.
12. Nabeta M, Yoshimoto H, Sato S, Hyakumachi T, Yanagibashi Y, Masuda T. Discal cysts of the lumbar spine. Report of five cases. J Neurosurg Spine. 2007 Jan; 6(1):85-9.
13. Koga H, Yone K, Yamamoto T, Komiya S. Percutaneous CT-guided puncture and steroid injection for the treatment of lumbar discal cyst: a case report. Spine (Philadelphia, PA 1976). 2003 Jun 1; 28(11):E212-6.
14. Chou D, Smith JS, Chin CT. Spontaneous regression of a discal cyst. Case report. J Neurosurg Spine. 2007 Jan; 6(1):81-4.
Author's Response to Case Discussion
I am extremely grateful to Dr. Jason Highsmith for the extensive review provided. I would also like to point out the fact that - but for discography, the diagnosis would not have been brought out in this case. Hence, discography is a very valuable technique, at least in a complex diagnostic dilemma like this.