Ependymoblastoma

This 2 year old was noted to have a head tilt for 1 week.  A well-circumscribed, enhancing lesion near the foramina of Luschka displaced the pons.

ependymoblastomarosette copy.jpg mitotic copy.jpg ependymoblastoma.jpg
 

Definition: A small cell, embryonal, CNS neoplasm with "ependymoblastic rosettes"

WHO Grade IV: PNET

Clinical features

  •  Occurs most often in childhood, median age at diagnosis 3 years
  •  Occasional congenital, Rare in adults
  •  Slight male predilection.
  •  68 % supratentorial locations, rare in leptomeninges,extradural sites
  •  Most common presenting symptoms are hydrocephalus and increased ICP. 

Imaging: Cystic lesion with vascular contrast enhancement

Histopathology

  • "True rosettes" and canals that are composed of multilayed, markedly atypical and mitotically active cells.
  • These pseudostratified"ependymoblastic rosettes" encircle a distinct lumen bounded by terminal bars
  • Geographical patterns of necrosis with pseudopalisading and microvascular hyperplasia in the form of endothelial proliferation are uncommon or absent. 

Immunohistochemistry

  • Rosettes are positive for vimentin and S100 but negative for GFAP

Differential diagnosis

  • Anaplastic ependymoma (Geographical patterns of necrosis with pseudopalisading and microvascular hyperplasia plus nuclear pleomorphism)
  • Embryonal tumor with abundant neuropil and true rosettes 
  • Malignant and immature teratoma
  • Medulloepitheliomas 

Treatment and Prognosis

  • Aggressive tumors
  • One study showed half of the patients died within a year of diagnosis
  • Median survival time was 12 months.
  • Widespread CSF dissemination is recognized. 

References

  • Surgical Pathology of the Nervous system and its Coverings, Fourth edition
  • Greenfield's Neuropathology,Sixth Edition
  • The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol. 2007 Aug;114(2):97-109.

About this Entry

This page contains a single entry by santa013 published on October 13, 2009 1:27 PM.

Meningioma with clear cell features was the previous entry in this blog.

Hypoxic-Ischemic encephalopathy is the next entry in this blog.

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