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Case 338 - Discussion

Uploaded: 2009-09-22, Updated: 2009-09-22

Anaplastic Ependymoma, WHO Grade III

 

 

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