Citation, DOI, disclosures and article data
At the time the article was created Sara Wein had no recorded disclosures.View Sara Wein's current disclosures
At the time the article was last revised Joshua Yap had no financial relationships to ineligible companies to disclose.View Joshua Yap's current disclosures
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 ependymomas and are the most common tumors of the cauda equina region.
On this page:
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.
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 hemorrhage 8.
They are thought to arise from the ependymal glia of the filum terminale.
The vast majority are intradural and extramedullary spinal tumors, 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.
Historically, myxopapillary ependymomas were considered grade I tumors, however, in the 5th edition (2021) of the WHO classification of CNS tumors they have been upgraded to grade 2 tumors in recognition of the fact that local recurrence is similar to that of other spinal cord ependymomas 12,13.
They are typically lobulated, encapsulated, and oval or sausage-shaped. They often have associated hemorrhage and may calcify or undergo cystic degeneration 9.
Histologically, they contain papillary elements arranged radially around a hyalinized fibrovascular core, forming perivascular pseudorosettes, with myxoid material between the blood vessel and tumor cells 9. "Balloons" (rounded eosinophilic PAS positive structures) are sometimes encountered 9.
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.
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.
They are well-defined intradural tumors. Classically, they present when larger and sausage-shaped, spanning more than one vertebral level, but small oval tumors are also seen. Smaller tumors tend to displace the nerve roots of the cauda equina; larger tumors often compress or encase them 8.
- usually isointense
- prominent mucinous component occasionally results in T1 hyperintensity
- hemorrhage and calcification can also lead to regions of hyper- or hypointensity
- overall high intensity
- low intensity may be seen at the tumor margins because of hemorrhage, called the cap sign (myxopapillary ependymomas are the subtype of ependymomas that are most prone to hemorrhage 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 hemorrhage present
Treatment and prognosis
Myxopapillary ependymomas are generally slow-growing but are considered WHO grade 2 tumors 13. Occasionally, CSF dissemination occurs and multiple lesions are seen in 14-43% cases 4. Some sacral lesions are locally aggressive and metastasize to lymph nodes, lungs, and bone. Aggressive behavior 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 tumor 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 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
- giant cell tumor: involving the spine
- 1. Brant WE, Helms CA. Fundamentals of Diagnostic Radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781761352. Read it at Google Books - Find it at Amazon
- 2. Osborn AG. Diagnostic neuroradiology. Mosby Inc. (1994) ISBN:0801674867. Read it at Google Books - Find it at Amazon
- 3. Grossman RI, Yousem DM. Neuroradiology, the requisites. Mosby Inc. (2003) ISBN:032300508X. Read it at Google Books - Find it at Amazon
- 4. Koeller KK, Rosenblum RS, Morrison AL. Neoplasms of the spinal cord and filum terminale: radiologic-pathologic correlation. Radiographics. 20 (6): 1721-49. Radiographics (citation) - Pubmed citation
- 5. Soderlund KA, Smith AB, Rushing EJ et-al. Radiologic-pathologic correlation of pediatric and adolescent spinal neoplasms: Part 2, Intradural extramedullary spinal neoplasms. AJR Am J Roentgenol. 2012;198 (1): 44-51. doi:10.2214/AJR.11.7121 - Pubmed citation
- 6. Cotran RS, Kumar V, Collins T et-al. Robbins pathologic basis of disease. W.B. Saunders Company. (1999) ISBN:072167335X. Read it at Google Books - Find it at Amazon
- 7. Abul-kasim K, Thurnher MM, Mckeever P et-al. Intradural spinal tumors: current classification and MRI features. Neuroradiology. 2008;50 (4): 301-14. doi:10.1007/s00234-007-0345-7 - Pubmed citation
- 8. Kahan H, Sklar EM, Post MJ et-al. MR characteristics of histopathologic subtypes of spinal ependymoma. AJNR Am J Neuroradiol. 1996;17 (1): 143-50. AJNR Am J Neuroradiol (citation) - Pubmed citation
- 9. Louis DN, Ohgaki H, Wiestler OD et-al. "WHO Classification of Tumours of the Central Nervous System. 4th Edition Revised" ISBN: 9789283244929
- 10. Weber DC, Wang Y, Miller R, Villà S, Zaucha R, Pica A, Poortmans P, Anacak Y, Ozygit G, Baumert B, Haller G, Preusser M, Li J. Long-term outcome of patients with spinal myxopapillary ependymoma: treatment results from the MD Anderson Cancer Center and institutions from the Rare Cancer Network. (2015) Neuro-oncology. 17 (4): 588-95. doi:10.1093/neuonc/nou293 - Pubmed
- 11. Koeller KK, Shih RY. Intradural Extramedullary Spinal Neoplasms: Radiologic-Pathologic Correlation. (2019) Radiographics : a review publication of the Radiological Society of North America, Inc. 39 (2): 468-490. doi:10.1148/rg.2019180200 - Pubmed
- 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. doi:10.1111/bpa.12866 - Pubmed
- 13. Louis D, Perry A, Wesseling P et al. The 2021 WHO Classification of Tumors of the Central Nervous System: A Summary. Neuro-Oncology. 2021;23(8):1231-51. doi:10.1093/neuonc/noab106 - Pubmed