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.
Definition: A small cell, embryonal, CNS neoplasm with "ependymoblastic rosettes"
WHO Grade IV: PNET
- 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
- "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.
- Rosettes are positive for vimentin and S100 but negative for GFAP
- 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
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.
- 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.