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Ependymomas

Last updated on Sunday, October 5 2008 by jdmiles

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Ependymomas are classified as glial tumors, although they also have epithelial properties.   They are common, accounting for 3%-9% of all brain tumors. 

They can occur at any age, but are somewhat more common in children.

40% of ependymomas occur in the first decade of life.

40% of ependymomas are supratentorial.  Supratentorial ependymomas are more common in adults than in children.

90% of ependymomas occur in the brain, 10% in the spinal cord.  Spinal cord ependymomas occur more frequently in adults than in children.  Ependymomas are the most common spinal cord gliomas.

As you might expect, they tend to occur where there are ependymal cells - the ventricles and the central canal of the spinal cord.  The most common location is the 4th ventricle.  

Typical microscopic features of ependymomas include rosettes and pseudorosettes.  Rosettes are epithelioid arrangements of tumor cells ito forma a central lumen.  In vascular pseudorosettes, there is no actual lumen.  Rather, the pseudorosettes represent radial processes that converge on a blood vessel. Rosettes are more specific for ependymomas, but are seen in only about 10% of cases.  Pseudorosettes are more common.

An example of a perivascular pseudorosette, cut longitudinally along the vessel:

 

An example of a true rosette:

 

There are several more examples of gross and microscopic images of ependymoma below.  Please explore the images.  Click on any of the thumbnails to see a larger image.

 

REFERENCES:

Radiographics. 2005 Mar-Apr;25(2):486-90.
Best cases from the AFIP: supratentorial ependymoma.
Mermuys K, Jeuris W, Vanhoenacker PK, Van Hoe L, D'Haenens P.
(PMID:15798065)

Prayson, R.A., and Goldblum, J.R. (Eds.) (2005). Neuropathology. Elsevier Churchill Livingstone, Philadelphia. (ISBN:0443066582)  Pages 468-476.

Allan H. Ropper, Robert H. Brown. Adams and Victor's Principles of Neurology, 8th edition. New York : McGraw-Hill Medical Pub. Division, 2005. (ISBN:007141620X)