CNS tumor
Ependymal tumors

Topic Completed: 1 August 2012

Minor changes: 24 August 2020

Copyright: (2002-2019,, Inc.

PubMed Search: Subependymoma [title]

Eman Abdelzaher, M.D., Ph.D.
Page views in 2019: 3,855
Page views in 2020 to date: 2,883
Cite this page: Abdelzaher E. Subependymoma. website. Accessed September 26th, 2020.
Definition / general
  • Benign slowly growing neoplasm typically attached to a ventricular wall
  • Cell of origin unknown but resembles subependymal tissue
  • Slow growing; 50% have symptoms (associated with larger size or specific locations, J Neurosurg 1978;49:689)
  • Affects middle aged to elderly adults, occasionally children
  • Usually occurs in fourth ventricle (50 - 60% of cases) or lateral ventricles (30 - 40%), often as incidental finding at autopsy; also spinal cord, where it usually presents as intramedullary mass
  • WHO Grade I of IV; benign behavior
Radiology description
  • Nonenhancing sharply demarcated, nodular mass
  • May be calcification or hemorrhage
  • Intraspinal examples are eccentric and show minimal to moderate enhancement
Radiology images

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Intraventricular mass

Case reports
  • Excision is usually curative, occasionally radiation therapy
Clinical images

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Fourth ventricle

Gross description
  • Well circumscribed, solid, gray white, sometimes calcified, protrudes into lateral ventricle or 4th ventricle
Microscopic (histologic) description
  • Clusters of isomorphic nuclei embedded in a dense, fine, glial fibrillary background
  • Mild nuclear pleomorphism, microcystic formations (especially in lateral ventricular tumors)
  • May be occasional ependymal pseudorosettes, hemorrhage, calcification
  • Rarely osseous metaplasia in childhood tumors (Neurol India 2003;51:9 (childhood cases))
  • No / rare mitoses
  • No necrosis no / rare endothelial proliferation
  • Classify as mixed ependymoma subependymoma if prominent ependymal component and grade based on ependymoma component
Microscopic (histologic) images

Contributed by Dr. Eman Abdelzaher

Bland nuclei, microcysts

Case of the Week #75

Contributed by Dr. David Taylor and Dr. Nazila Azordegan




Dot-like perinuclear (EMA)

40x (EMA)

Cytology description
  • Microcystic formations, loose fibrillary networks and nuclear clusters with mild pleomorphism (Acta Cytol 2001;45:636)
Positive stains
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