Case 8133 Double ependymoma of the spinal cord in

Case 8133 Double ependymoma of the spinal cord in a 5-year-old boy Kraniotis P1, Sdougos G2, Zampakis P1, Romanos O1, Solomou E1 1. Magetic Resonance Department, University Hospital of Patras, Rion, Patras, Greece. 2. Department of Orthopedic Surgery, Karamandaneion Children's Hospital, Patras, Greece Section: Paediatric Radiology Published: 2010, Apr. 18 Patient: 5 year(s), male

Clinical History A 5-year-old boy presented with low back pain during the last 4 days. Physical examination revealed regional rigidity. Spinal MR depicted two tumors in the spinal canal, one in the cauda equina and another in the thoraco-lumbar junction, which were surgically resected. Histology confirmed a benign myxopapillary ependymoma, type I.

Imaging Findings A 5 year old boy was referred to our hospital complaining of low back pain for the last 4 days. Physical examination revealed rigidity, while plain X-rays were unremarkable. Further investigation with MRI of the lumbar spine was deemed necessary. The patient was examined with a 1-Tesla MRI unit. Images were obtained in both axial and sagittal planes with T1, T2 weighted images (WI) as well as short tau inversion recovery (STIR) images. There was high signal intensity on the STIR images, within the spinal cord, from the level of D11-12 intervertebral disc up to S2 vertebra, suggestive of intraspinal oedema. On T1WI the lesion was inhomogeneously hypointense (Fig 1), and hyperintense on STIR images (Fig 2). A fluid-fluid level was noted on both sequences. After the administration of gadolinium the lesions exhibited avid enhancement with well-defined borders. The first lesion was located at the level of D11-12 intervertebral disk up to L2 vertebra and the second at the level of S1 up to S2 vertebrae. The spinal cord was markedly

expanded (Fig 3).The differential included ependymoma and astrocytoma. The patient underwent surgical partial resection of the tumour. The histological examination revealed a benign myxopapillary ependymoma, type I.

Discussion Ependymomas originate from the cells lining the internal surfaces of the ventricles and the central canal of the spinal cord. They may occur anywhere in the neuraxis. In the first two decades of life, they characteristically originate in the 4th ventricle, representing 5-10% of primitive encephalic tumours in that age group. In adults, the most frequent localization is the spinal cord. There are two types of ependymomas: non-anaplastic (papillary, myxopapillary and subependymoma) and anaplastic (ependymoblastoma). The myxopapillary form arises mainly in the conus medullaris, cauda equina and filum terminale and is the most frequent type during the fourth decade of life. Intramedullary spinal cord tumours are very rare in children, with low-grade astrocytomas representing the most common type. The cervical spine is the region most often affected. Only 8-14% affects the filum terminale, and only one forth of these are of the myxopapillary subtype. This type is usually a solitary tumour but occasionally can be found at more cephalic spinal levels. In our patient, the tumour appeared in two regions, one in the terminal filum and the other in thethoracolumbar spine. Children usually present with back, neck or radicular pain. While sphincter and sensory dysfunction, numbness, motor disturbances, torticollis and scoliosis are less common. The disease may also be asymptomatic or cause nonspecific symptoms, like abdominal pain. The average duration of symptoms is 13.3 months, with a mean age of diagnosis of 5.6 years. Plain radiographs, may reveal erosion of the pedicles or of the posterior surface of the vertebral bodies. CT can localize the lesion and depict its extension into the spinal canal, while at the same time it can provide evidence of microcalcifications, which are not evident with MRI. On the other than MRI is the favoured modality, providing superior depiction of the lesion without ionizing radiation, which must be taken in consideration when imaging children. It also has the advantage of evaluating extension of the tumour in different planes, which is helpful for surgical planning. On T1WI myxopapillary ependymoma is usually hypo- to isointense, compared to spinal cord and heterogeneously hyperintense on T2WI. After the administration of gadolinium shows intense irregular enhancement. Areas of haemorrhage or hemosiderin deposition at the superior and inferior borders can sometimes be depicted. Widening of the spinal cord is not rare. The diagnosis of ependymoma can be sugested based upon imaging characteristics and patient age, though MRI imaging is not specific and histologic examination is finally necessary. Surgical resection of intramedullary tumours is the only effective treatment, but with high rates of recurrence if the lesion is not completely resected. Radiotherapy should only be administrated to malignant gliomas and recurrences or in tumours partially removed. The reported mean survival period is six years.

Final Diagnosis Double ependymoma of the spinal cord

Figures

Figure 1 Sag T1WI

Sagittal T1 TSE demonstrates inhomogeneously low signal intensity from D11-TH12 up to S2 level with widening of the cord. Figure 2 Sag STIR image

Sagittal STIR demonstrates high signal intensity in the spinal cord from D12-S2 and a fluid-fluid level within the lesion. Figure 3 Sag T1 with fat suppression and gadolinium

There are two intraspinal lesions with intense enhancement at the level of the thoraco-lumbar junction and S1-S2 level.

MeSH Spinal Cord [A08.186.854] Spinal Cord Neoplasms [C04.588.614.250.803] Benign and malignant neoplasms which occur within the substance of the spinal cord (intramedullary neoplasms) or in the space between the dura and spinal cord (intradural extramedullary neoplasms). The majority of intramedullary spinal tumors are primary CNS neoplasms including ASTROCYTOMA; EPENDYMOMA; and LIPOMA. Intramedullary neoplasms are often associated with SYRINGOMYELIA. The most frequent histologic types of intradural-extramedullary tumors are MENINGIOMA and NEUROFIBROMA.

References [1] Hallacq P, Labrousse F, Streichenberger N, Lisii D, Fischer G. Bifocal myxopapillary ependymoma of the terminal filum: the end of a spectrum? Case report. J Neurosurg Spine. 2003 Apr; 98(3): 288-9. [2] Gelabert-Gonzalez M, Prieto-Gonzalez A, Abdulkader-Nallib I, Cutrin-Prieto J. Double ependymoma of the filum terminale. Childs Nerv Syst. 2001 Jan; 17(1-2): 106-8. [3] Kumar V, Solanki RS. Myxopapillary ependymoma of the filum terminale. Pediatr Radiol. 2009 Apr;39(4):415. Epub 2009 Feb 20. [4] Nakama S, Higashi T, Kimura A, Yamamuro K, Kikkawa I, Hoshino Y. Double myxopapillary ependymoma of the cauda equina. J Orthop Sci. 2005 Sep;10(5):543-5.

Citation Kraniotis P1, Sdougos G2, Zampakis P1, Romanos O1, Solomou E1 1. Magetic Resonance Department, University Hospital of Patras, Rion, Patras, Greece. 2. Department of Orthopedic Surgery, Karamandaneion Children's Hospital, Patras, Greece (2010, Apr. 18) Double ependymoma of the spinal cord in a 5-year-old boy {Online} URL: http://www.eurorad.org/case.php?id=8133