Myxopapillary ependymoma
Updates to Article Attributes
Myxopapillary ependymomas are a variant type of ependymoma that occurs predominantly in the filum terminale and/or conus medullaris. They represent 13% of all spinal ependymomasand are the most common tumorstumours of the cauda equina region.
Epidemiology
They tend to have an earlier clinical presentation than other spinal ependymomas, with a mean age of presentation of 35 years. There is a slight male predominance.
Clinical presentation
The most common presenting symptoms are low back, leg or sacral pain. Up to 25% of patients may present with leg weakness or sphincter dysfunction.
They may occasionally present as a subarachnoid haemorrhage 8.
Pathology
Aetiology
They are thought to arise from the ependymal glia of the filum terminale.
Location
The vast majority are intradural and extramedullary spinal tumours, occurring in the lumbosacral spine involving the filum terminale and/or conus medullaris. Less commonly, they extend from the lumbar to the thoracic spine 10. Rarely, they can arise in the cervicothoracic spine or fourth ventricle 11.
Grading
Historically, myxopapillary ependymomas were considered grade I tumours, however, in the 5th edition (2021) of the WHO classification of CNS tumours they have been upgraded to grade 2 tumours in recognition of the fact that local recurrence is similar to that of other spinal cord ependymomas 12,13.
Macroscopic appearance
They are typically lobulated, encapsulated, and oval or sausage-shaped. They often have associated haemorrhage and may calcify or undergo cystic degeneration 9.
Microscopic appearance
Histologically, they contain papillary elements arranged radially around a hyalinized fibrovascular core, forming perivascular pseudorosettes, with myxoid material between the blood vessel and tumour cells 9. "Balloons" (rounded eosinophilic PAS positive structures) are sometimes encountered 9.
Immunophenotype
As is the case with ependymomas generally, myxopapillary ependymomas are GFAP, S100, and vimentin positive 9. CD99, AE1/AE3 and NCAM1 are also commonly positive 9.
Radiographic features
Plain radiograph / CT
If they become large, myxopapillary ependymomas may expand the spinal canal, cause scalloping of the vertebral bodies and extend out of the neural exit foramina.
MRI
They are well-defined intradural tumours. Classically, they present when larger and sausage-shaped, spanning more than one vertebral level, but small oval tumours are also seen. Smaller tumours tend to displace the nerve roots of the cauda equina; larger tumours often compress or encase them 8.
Signal characteristics
-
T1
- usually isointense
- prominent mucinous component occasionally results in T1 hyperintensity
- haemorrhage and calcification can also lead to regions of hyper- or hypointensity
-
T2
- overall high intensity
- low intensity may be seen at the tumour margins because of haemorrhage, called the cap sign (myxopapillary ependymomas are the subtype of ependymomas that are most prone to haemorrhage 8)
- calcification may also lead to regions of low T2 signal
-
T1 C+ (Gd)
- enhancement is virtually always seen
- the enhancement pattern is typically homogeneous. However, they can have a variable enhancement pattern that, in part, depends on the amount of haemorrhage present
Treatment and prognosis
Myxopapillary ependymomas are generally slow-growing but are considered WHO grade 2 tumours 13. Occasionally, CSF dissemination occurs and multiple lesions are seen in 14-43% cases 4. Some sacral lesions are locally aggressive and metastasise to lymph nodes, lungs, and bone. Aggressive behaviour is more commonly seen in children 9.
They can often be excised completely. In these cases, the prognosis is excellent, with 5-year-survival over 98% 9.
If the tumour has extended to the conus medullaris, resection is often incomplete, with a greater risk of local recurrence, and there is a greater risk of neurologic deficit 11.
Differential diagnosis
Differential diagnosis of a small conus and filum terminale myxopapillary ependymoma includes:
Differential diagnosis of a large myxopapillary ependymoma that causes sacral destruction:
- aneurysmal bone cyst: involving the spine
- chordoma
- giant cell tumour: involving the spine
See also
-<p><strong>Myxopapillary ependymomas</strong> are a variant type of <a href="/articles/spinal-ependymoma">ependymoma</a> that occurs predominantly in the <a href="/articles/filum-terminale">filum terminale</a> and/or <a href="/articles/conus-medullaris">conus medullaris</a>. They represent 13% of all spinal ependymomas<sup> </sup>and are the most common <a href="/articles/neoplasms-of-the-cauda-equina-differential">tumors of the cauda equina region</a>.</p><h4>Epidemiology</h4><p>They tend to have an earlier clinical presentation than other spinal ependymomas, with a mean age of presentation of 35 years. There is a slight male predominance.</p><h4>Clinical presentation</h4><p>The most common presenting symptoms are low back, leg or sacral pain. Up to 25% of patients may present with leg weakness or sphincter dysfunction.</p><p>They may occasionally present as a <a href="/articles/subarachnoid-haemorrhage">subarachnoid haemorrhage</a> <sup>8</sup>.</p><h4>Pathology</h4><h5>Aetiology</h5><p>They are thought to arise from the ependymal glia of the <a href="/articles/filum-terminale">filum terminale</a>. </p><h5>Location</h5><p>The vast majority are <a href="/articles/intradural-extramedullary-spinal-tumours-1">intradural and extramedullary</a> spinal tumours, occurring in the lumbosacral spine involving the <a href="/articles/filum-terminale">filum </a><a href="/articles/filum-terminale">terminale</a> and/or <a href="/articles/conus-medullaris">conus medullaris</a>. Less commonly, they extend from the lumbar to the thoracic spine <sup>10</sup>. Rarely, they can arise in the cervicothoracic spine or fourth ventricle <sup>11</sup>.</p><h5>Grading</h5><p>Historically, myxopapillary ependymomas were considered grade I tumours, however, in the 5th edition (2021) of the <a href="/articles/who-classification-of-cns-tumours-1">WHO classification of CNS tumours</a> they have been upgraded to grade 2 tumours in recognition of the fact that local recurrence is similar to that of other <a title="Spinal ependymoma" href="/articles/spinal-ependymoma">spinal cord ependymomas</a> <sup>12,13</sup>.</p><h5>Macroscopic appearance</h5><p>They are typically lobulated, encapsulated, and oval or sausage-shaped. They often have associated haemorrhage and may calcify or undergo cystic degeneration <sup>9</sup>.</p><h5>Microscopic appearance</h5><p>Histologically, they contain papillary elements arranged radially around a hyalinized fibrovascular core, forming <a href="/articles/perivascular-pseudorosettes-ependymoma">perivascular pseudorosettes</a>, with myxoid material between the blood vessel and tumour cells <sup>9</sup>. "Balloons" (rounded eosinophilic PAS positive structures) are sometimes encountered <sup>9</sup>. </p><h5>Immunophenotype</h5><p>As is the case with ependymomas generally, myxopapillary ependymomas are <a href="/articles/glial-fibrillary-acid-protein-gfap">GFAP</a>, <a href="/articles/s100">S100</a>, and <a href="/articles/vimentin">vimentin</a> positive <sup>9</sup>. CD99, AE1/AE3 and NCAM1 are also commonly positive <sup>9</sup>. </p><h4>Radiographic features</h4><h5>Plain radiograph / CT</h5><p>If they become large, myxopapillary ependymomas may expand the spinal canal, cause scalloping of the vertebral bodies and extend out of the neural exit foramina.</p><h5>MRI</h5><p>They are well-defined intradural tumours. Classically, they present when larger and sausage-shaped, spanning more than one vertebral level, but small oval tumours are also seen. Smaller tumours tend to displace the nerve roots of the cauda equina; larger tumours often compress or encase them <sup>8</sup>.</p><h6>Signal characteristics</h6><ul>- +<p><strong>Myxopapillary ependymomas</strong> are a variant type of <a href="/articles/spinal-ependymoma">ependymoma</a> that occurs predominantly in the <a href="/articles/filum-terminale">filum terminale</a> and/or <a href="/articles/conus-medullaris">conus medullaris</a>. They represent 13% of all spinal ependymomas<sup> </sup>and are the most common <a href="/articles/neoplasms-of-the-cauda-equina-differential">tumours of the cauda equina region</a>.</p><h4>Epidemiology</h4><p>They tend to have an earlier clinical presentation than other spinal ependymomas, with a mean age of presentation of 35 years. There is a slight male predominance.</p><h4>Clinical presentation</h4><p>The most common presenting symptoms are low back, leg or sacral pain. Up to 25% of patients may present with leg weakness or sphincter dysfunction.</p><p>They may occasionally present as a <a href="/articles/subarachnoid-haemorrhage">subarachnoid haemorrhage</a> <sup>8</sup>.</p><h4>Pathology</h4><h5>Aetiology</h5><p>They are thought to arise from the ependymal glia of the <a href="/articles/filum-terminale">filum terminale</a>. </p><h5>Location</h5><p>The vast majority are <a href="/articles/intradural-extramedullary-spinal-tumours-1">intradural and extramedullary</a> spinal tumours, occurring in the lumbosacral spine involving the <a href="/articles/filum-terminale">filum </a><a href="/articles/filum-terminale">terminale</a> and/or <a href="/articles/conus-medullaris">conus medullaris</a>. Less commonly, they extend from the lumbar to the thoracic spine <sup>10</sup>. Rarely, they can arise in the cervicothoracic spine or fourth ventricle <sup>11</sup>.</p><h5>Grading</h5><p>Historically, myxopapillary ependymomas were considered grade I tumours, however, in the 5th edition (2021) of the <a href="/articles/who-classification-of-cns-tumours-1">WHO classification of CNS tumours</a> they have been upgraded to grade 2 tumours in recognition of the fact that local recurrence is similar to that of other <a href="/articles/spinal-ependymoma">spinal cord ependymomas</a> <sup>12,13</sup>.</p><h5>Macroscopic appearance</h5><p>They are typically lobulated, encapsulated, and oval or sausage-shaped. They often have associated haemorrhage and may calcify or undergo cystic degeneration <sup>9</sup>.</p><h5>Microscopic appearance</h5><p>Histologically, they contain papillary elements arranged radially around a hyalinized fibrovascular core, forming <a href="/articles/perivascular-pseudorosettes-ependymoma">perivascular pseudorosettes</a>, with myxoid material between the blood vessel and tumour cells <sup>9</sup>. "Balloons" (rounded eosinophilic PAS positive structures) are sometimes encountered <sup>9</sup>. </p><h5>Immunophenotype</h5><p>As is the case with ependymomas generally, myxopapillary ependymomas are <a href="/articles/glial-fibrillary-acid-protein-gfap">GFAP</a>, <a href="/articles/s100">S100</a>, and <a href="/articles/vimentin">vimentin</a> positive <sup>9</sup>. CD99, AE1/AE3 and NCAM1 are also commonly positive <sup>9</sup>. </p><h4>Radiographic features</h4><h5>Plain radiograph / CT</h5><p>If they become large, myxopapillary ependymomas may expand the spinal canal, cause scalloping of the vertebral bodies and extend out of the neural exit foramina.</p><h5>MRI</h5><p>They are well-defined intradural tumours. Classically, they present when larger and sausage-shaped, spanning more than one vertebral level, but small oval tumours are also seen. Smaller tumours tend to displace the nerve roots of the cauda equina; larger tumours often compress or encase them <sup>8</sup>.</p><h6>Signal characteristics</h6><ul>
-<li><a href="/articles/spinal-paraganglioma">paraganglioma</a></li>- +<li><a href="/articles/spinal-neuroendocrine-tumour">paraganglioma</a></li>
References changed:
- 12. Ellison D, Aldape K, Capper D et al. CIMPACT‐NOW Update 7: Advancing the Molecular Classification of Ependymal Tumors. Brain Pathol. 2020;30(5):863-6. <a href="https://doi.org/10.1111/bpa.12866">doi:10.1111/bpa.12866</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/32502305">Pubmed</a>
- 12. David W. Ellison, Kenneth D. Aldape, David Capper, Maryam Fouladi, Mark R. Gilbert, Richard J. Gilbertson, Cynthia Hawkins, Thomas E. Merchant, Kristian Pajtler, Sriram Venneti, David N. Louis. cIMPACT‐NOW update 7: advancing the molecular classification of ependymal tumors. (2020) Brain Pathology. 30 (5): 863. <a href="https://doi.org/10.1111/bpa.12866">doi:10.1111/bpa.12866</a> <span class="ref_v4"></span>
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