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	Ependymoma	Medulloblastoma	Atypical teratoid/rhabdoid tumor
Age	6.4 years	7 years	2 years
Location	4th ventricle	Vermis, projects into 4th ventricle	Supra- or infratentorial
Gross	Soft tan, well-circumscribed mass	Pink, grey mass	Soft, pink, red, bulky. Often extensive necrosis and hemorrhage.
Micro	Well-circumscribed. Alternative cellular and less cellular areas. Perivascular pseudorosettes, common. True ependymal rosettes, uncommon. Monomorphic, round/oval nuclei, salt and pepper chromatin. Frequent more fibrillarity. Rare or absent mitosis. Common hyalinized vessels and calcification	Densely cellular, relatively small cell. Round, oval, carrot shape, hyperchromatic. Scant cytoplasm. Many mitoses. Homer-Wright rosettes Ganglioid or ganglion cells Calcification is uncommon	Sheets of tumor cells Broad and edematous fibrovascular septa. Areas of epithelial and PNET-like Large areas of hemorrhage and necrosis Abundant mitoses Rhabdoid cells
WHO Grade	II	IV	IV
IPX	GFAP: + in pseudorosettes. EMA: + dot like S100: + CK AE1/3: focally + CD99: +	Synaptophysin:+ NSE: + Neurofilament: less commonly + GFAP: + in fibrillar areas	EMA: + Vimentin: + SMA: + GFAP: + CK: + Synaptophysin occasionally + INI1-
EM	Cilia 9+2 arrangement, luminal microvilli	Neurite cytoplasmic processes.
Cytogenetics	del(22q11) , NF2 gene, 30%	del(17p), 30-40%	Mutation/deletion of INI1 on 22q11