The Neuroradiology Journal 19: 379-381, 2006
www. centauro. it
Synovial Cyst of Dens Axis A Case Report G. RIVA, C.G. PUGLISI, A. GIUDICE, R. PAPA, T. CAVALLARO*, I. CHIARAMONTE, G. PERO U.O. di Neuroradiologia; * Istituto di Neurologia, Università degli Studi di Catania, Azienda Ospedaliero-Universitaria, Policlinico di Catania, Italy
Key words: synovial cyst, dens axis, mdtc, mri, mip
SUMMARY – Synovial cyst of dens axis is a rare pathology accounting for 0.5%-1% of all cases of spinal synovial cysts. The lesion is normally found in the final part of the lumbar tract. The etiopathogenesis is uncertain and many theories abound Clinical inspection is important and the symptoms are caused by compression of posterior roots of spinal nerves and by spinal canal stenosis. Differential diagnosis is with disc herniation or tumours, but the diagnosis can only be established after CT and MRI examination. We describe the case of an 83-year-old man who underwent radiological exmaination after ten years of symptoms. The pathology was diagnosed only after the CT and MRI investigation.
Introduction Synovial cyst of dens axis is a rare pathology so its diagnosis is not straightforward. The pathology was first described by Shollner in 1967. Synovial cysts are commonly located in the final part of the lumbar tract 1,2,3. The etiopathogenesis is uncertain 4,5,6. The most common theory claims that spondylolisthesis, elderly age, intervertebral joints instability and microtraumas are important causes because they partially damage joint cartilage and create a route for the passage of synovial fluid producing synovial cyst 7,8. Patients with rheumatoid arthritis have been found to develop synovial cyst more frequently than the normal population 9. Clinical signs of synovial cyst are caused by displacement and compression of the posterior roots of the spinal nerves and spinal canal stenosis. The most common signs are severe pain, neurological failure such as ataxia, paresthesia, tingling, numbness of the skin and paresis 10. The initial signs are similar to disc herniation pathology. CT and MRI are indispensable for diagnosis.
Therapy depends on size and symptoms. The cyst can be treated by percutaneous aspiration, local cortisone injection, FANS or surgical excision. Surgery is indispensable if there is neurological failure. Case Report We used an MDCT system with a spiral CT protocol that permitted us to acquire large volumes. 160 ml of iodate contrast medium were injected; the parameters were 140 Kv, 300 mA, 1.5 mm slice thickness, reconstruction interval of 0.6 mm. A workstation GE Advantage Windows 4.0 reformatted axial and coronal images with excellent results. We use 3D volume rendering software and shaded surface rendering that helps us in the differential diagnosis of tumours. It is also important to utilize MRI to eastablish an accurate diagnosis. We used a GE MRI with 1.5 Tesla, obtaining axial, sagittal and coronal images T1 and T2 weighted and T1 weighted with contrast (gadolinium 2 ml/kg). 379
Synovial Cyst of Dens Axis. A Case Report
G. Riva
➡
Figure 1 FSE coronal T2-weighted image: the lesion has high signal intensity.
Figure 2 FSE coronal T2-weighted image: lesion with spinal cord compression.
We examined an 83-year-old man who suffers from deformans arthritis with major failure of the lumbosacral and knee joints. This disease began when he was 73. In recent months it was noticed that thepatient’s disease was more serious: not only pain in the backbone but also paresthesia, tingling, numbness of the skin. Electromyography disclosed a tunnel carpal syndrome, an ulnar nerve entrapment and legs polymyopathy. The symptoms became increasingly severe and we also noticed that the patient began to have deambulation pathology. Spinal CT scan demonstrated a large lesion with liquid and solid parts located all around the dens axis causing a compression of the spine. The diagnosis of a similar lesion is not so easy so we did an MR examination which showed that the lesion had a low signal intensity (hypointense) on T1 weighted images, high signal intensity on T2. It could be differentiated from meningioma, because synovial cyst does not present massive enhancement, dural tail, calcifications and absence of peripheral signal. Our definite diagnosis was synovial cyst of the dens axis.
Discussion
380
This case report describes the value of MRI images which are sometime the only means to establish diagnosis. In fact, CT images were not sufficient and left many doubts about the final diagnosis. Moreover the possibility to study the case report over time represents another great advantage to see a healthy patient after therapy. Unfortunately the major disadvantage of MRI is its price tag. Conclusion Synovial cyst of the dens axis is uncommon and therefore difficult to recognize. In the last year the possibility to study and see these kind of lesions directly on CT and MRI images allowed us to notice this lesion also in patients without symptoms. So the incidence of this disease is increased 11. Differential diagnosis with disc herniation and tumour is of primary importance 12. Microsurgery treatment is required if the lesion does not respond to steroids and pain is severe.
www. centauro. it
The Neuroradiology Journal 19: 379-381, 2006
➡
Figure 3 FSE coronal T2-weighted image: the lesion has high signal intensity.
Figure 4 FSE coronal T2-weighted lesion with severe compression of the posterior roots of the spinal nerves and spinal cord.
References 1 Choe W, Walot I, Sclesinger C et Al. Synovial cyst of dens causing spinal cord compression. Case report. Paraplegia 31: 803-7, 1993. 1 Brish A, Payan HJ: Lumbar intraspinal extradural ganglion cyst. Neurol Neurosurger Psychiatric 35: 7715, 1972. 3 Phuong loi K, Atkinson John LD, Thielen et Al: Far lateral extraforaminal lumbar synovial cyst: report of two cases. Neurosurgery 51: 505-508, 2002. 4 Onofrio BM, Mih AD: Synovial cysts of the spine. Neurosurgery 22: 642-7, 1988. 5 Patel SC, Sanders WP: Synovial cyst of the cervical spine: case report and review of the literature. Am J Neuroradiology 9: 602-3, 1988. 6 Pendetlon B, Carl B, Polaay M: Spinal extradural benign synovial or ganglion cyst: case report and review of the literature. Neurosurgery 13: 322-6, 1983. 7 Cai, Christopher Y, Palmer et Al: Exuberant transverse ligament degeneration causing high cervical myelopathy. Journalof Spinal Disorders 14: 84-88, 2001. 8 Okamoto K, Doita M, Yoshikawa M et Al: Synovial cyst at C1-C2 junction in a patient with atloaxial subluxation. Journal of Spinal Disorders & Techniques 17: 535-538, 2004. 9 Morio Y, Yoshioka T, Nagashima H et Al: Intraspinal synovial cyst communicating with C1-C2 facet joints and subaracnoid space associated with rheumatoid atlantoaxial instability. Spine 28: 492, 2004. 10 Fonoff ET, Dias MP, Tarico MA: Myelopathic presentation of cervical juxtafacet cyst: a case report. Spine 29: 538-541, 2004. 11 Tomokazu Ito, Masahiro Hayashy, Toshihiko Ogino: Retrodental synovial cyst which disappeared after posterior C1-C2 fusion: a case report. Journal of Orthopaedic Surgery, June 2000.
Figure 5 FSE axial T2-weighted image: lesion with compression of the posterior root of the left spinal nerve and spinal canal stenosis. Dr G. Riva U.O. di Neuroradiologia - Università degli Studi di Catania Azienda Ospedaliero-Universitaria - Policlinico di Catania Via S. Sofia, 78 95123 Catania - Italia Tel.: 095 3781111 E-mail: [email protected]
381
www. centauro. it
Synovial Cyst of Dens Axis A Case Report G. RIVA, C.G. PUGLISI, A. GIUDICE, R. PAPA, T. CAVALLARO*, I. CHIARAMONTE, G. PERO U.O. di Neuroradiologia; * Istituto di Neurologia, Università degli Studi di Catania, Azienda Ospedaliero-Universitaria, Policlinico di Catania, Italy
Key words: synovial cyst, dens axis, mdtc, mri, mip
SUMMARY – Synovial cyst of dens axis is a rare pathology accounting for 0.5%-1% of all cases of spinal synovial cysts. The lesion is normally found in the final part of the lumbar tract. The etiopathogenesis is uncertain and many theories abound Clinical inspection is important and the symptoms are caused by compression of posterior roots of spinal nerves and by spinal canal stenosis. Differential diagnosis is with disc herniation or tumours, but the diagnosis can only be established after CT and MRI examination. We describe the case of an 83-year-old man who underwent radiological exmaination after ten years of symptoms. The pathology was diagnosed only after the CT and MRI investigation.
Introduction Synovial cyst of dens axis is a rare pathology so its diagnosis is not straightforward. The pathology was first described by Shollner in 1967. Synovial cysts are commonly located in the final part of the lumbar tract 1,2,3. The etiopathogenesis is uncertain 4,5,6. The most common theory claims that spondylolisthesis, elderly age, intervertebral joints instability and microtraumas are important causes because they partially damage joint cartilage and create a route for the passage of synovial fluid producing synovial cyst 7,8. Patients with rheumatoid arthritis have been found to develop synovial cyst more frequently than the normal population 9. Clinical signs of synovial cyst are caused by displacement and compression of the posterior roots of the spinal nerves and spinal canal stenosis. The most common signs are severe pain, neurological failure such as ataxia, paresthesia, tingling, numbness of the skin and paresis 10. The initial signs are similar to disc herniation pathology. CT and MRI are indispensable for diagnosis.
Therapy depends on size and symptoms. The cyst can be treated by percutaneous aspiration, local cortisone injection, FANS or surgical excision. Surgery is indispensable if there is neurological failure. Case Report We used an MDCT system with a spiral CT protocol that permitted us to acquire large volumes. 160 ml of iodate contrast medium were injected; the parameters were 140 Kv, 300 mA, 1.5 mm slice thickness, reconstruction interval of 0.6 mm. A workstation GE Advantage Windows 4.0 reformatted axial and coronal images with excellent results. We use 3D volume rendering software and shaded surface rendering that helps us in the differential diagnosis of tumours. It is also important to utilize MRI to eastablish an accurate diagnosis. We used a GE MRI with 1.5 Tesla, obtaining axial, sagittal and coronal images T1 and T2 weighted and T1 weighted with contrast (gadolinium 2 ml/kg). 379
Synovial Cyst of Dens Axis. A Case Report
G. Riva
➡
Figure 1 FSE coronal T2-weighted image: the lesion has high signal intensity.
Figure 2 FSE coronal T2-weighted image: lesion with spinal cord compression.
We examined an 83-year-old man who suffers from deformans arthritis with major failure of the lumbosacral and knee joints. This disease began when he was 73. In recent months it was noticed that thepatient’s disease was more serious: not only pain in the backbone but also paresthesia, tingling, numbness of the skin. Electromyography disclosed a tunnel carpal syndrome, an ulnar nerve entrapment and legs polymyopathy. The symptoms became increasingly severe and we also noticed that the patient began to have deambulation pathology. Spinal CT scan demonstrated a large lesion with liquid and solid parts located all around the dens axis causing a compression of the spine. The diagnosis of a similar lesion is not so easy so we did an MR examination which showed that the lesion had a low signal intensity (hypointense) on T1 weighted images, high signal intensity on T2. It could be differentiated from meningioma, because synovial cyst does not present massive enhancement, dural tail, calcifications and absence of peripheral signal. Our definite diagnosis was synovial cyst of the dens axis.
Discussion
380
This case report describes the value of MRI images which are sometime the only means to establish diagnosis. In fact, CT images were not sufficient and left many doubts about the final diagnosis. Moreover the possibility to study the case report over time represents another great advantage to see a healthy patient after therapy. Unfortunately the major disadvantage of MRI is its price tag. Conclusion Synovial cyst of the dens axis is uncommon and therefore difficult to recognize. In the last year the possibility to study and see these kind of lesions directly on CT and MRI images allowed us to notice this lesion also in patients without symptoms. So the incidence of this disease is increased 11. Differential diagnosis with disc herniation and tumour is of primary importance 12. Microsurgery treatment is required if the lesion does not respond to steroids and pain is severe.
www. centauro. it
The Neuroradiology Journal 19: 379-381, 2006
➡
Figure 3 FSE coronal T2-weighted image: the lesion has high signal intensity.
Figure 4 FSE coronal T2-weighted lesion with severe compression of the posterior roots of the spinal nerves and spinal cord.
References 1 Choe W, Walot I, Sclesinger C et Al. Synovial cyst of dens causing spinal cord compression. Case report. Paraplegia 31: 803-7, 1993. 1 Brish A, Payan HJ: Lumbar intraspinal extradural ganglion cyst. Neurol Neurosurger Psychiatric 35: 7715, 1972. 3 Phuong loi K, Atkinson John LD, Thielen et Al: Far lateral extraforaminal lumbar synovial cyst: report of two cases. Neurosurgery 51: 505-508, 2002. 4 Onofrio BM, Mih AD: Synovial cysts of the spine. Neurosurgery 22: 642-7, 1988. 5 Patel SC, Sanders WP: Synovial cyst of the cervical spine: case report and review of the literature. Am J Neuroradiology 9: 602-3, 1988. 6 Pendetlon B, Carl B, Polaay M: Spinal extradural benign synovial or ganglion cyst: case report and review of the literature. Neurosurgery 13: 322-6, 1983. 7 Cai, Christopher Y, Palmer et Al: Exuberant transverse ligament degeneration causing high cervical myelopathy. Journalof Spinal Disorders 14: 84-88, 2001. 8 Okamoto K, Doita M, Yoshikawa M et Al: Synovial cyst at C1-C2 junction in a patient with atloaxial subluxation. Journal of Spinal Disorders & Techniques 17: 535-538, 2004. 9 Morio Y, Yoshioka T, Nagashima H et Al: Intraspinal synovial cyst communicating with C1-C2 facet joints and subaracnoid space associated with rheumatoid atlantoaxial instability. Spine 28: 492, 2004. 10 Fonoff ET, Dias MP, Tarico MA: Myelopathic presentation of cervical juxtafacet cyst: a case report. Spine 29: 538-541, 2004. 11 Tomokazu Ito, Masahiro Hayashy, Toshihiko Ogino: Retrodental synovial cyst which disappeared after posterior C1-C2 fusion: a case report. Journal of Orthopaedic Surgery, June 2000.
Figure 5 FSE axial T2-weighted image: lesion with compression of the posterior root of the left spinal nerve and spinal canal stenosis. Dr G. Riva U.O. di Neuroradiologia - Università degli Studi di Catania Azienda Ospedaliero-Universitaria - Policlinico di Catania Via S. Sofia, 78 95123 Catania - Italia Tel.: 095 3781111 E-mail: [email protected]
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