Brain Tumor Res Treat.  2017 Oct;5(2):127-130. 10.14791/btrt.2017.5.2.127.

Extra-Axial and Clear Cell Type Ependymoma, Mimicking a Convexity Meningioma

• Ahn S
• Kim YJ
• Lee YS
• Jeun SS

• KMID: 2396459
• DOI: http://doi.org/10.14791/btrt.2017.5.2.127

Abstract

A 33-year-old woman presented with tingling and paresthesia on left extremity for 2 months. Magnetic resonance imaging revealed that the tumor was iso- and hypo-intensity on T1-weighted image, mixed iso- and high-signal intensity on T2-weighted images and heterogeneously enhanced with rim enhancement. Neither arachnoid cleft nor dural tail was certain but mass was located extra-axially so meningioma was suspected. During operation, tumor wasn't attached to dura at all but arachnoid attachment was seen. Pathologically, clear cell type ependymoma was confirmed. Details of diagnosis and treatment of this tumor is described.

Keyword

Ependymoma; Meningioma

MeSH Terms

Adult
Arachnoid
Diagnosis
Ependymoma*
Extremities
Female
Humans
Magnetic Resonance Imaging
Meningioma*
Paresthesia
Tail

Figure

• 

  Fig. 1 A contrast-enhanced magnetic resonance imaging showed 41×42×29 mm sized extra-axial and heterogeneously enhanced mass on right parietal convexity, which seems to be originated from meninges, but dural-tail sign wasn't significant.

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  Fig. 2 Operative findings of extra-axial ependymoma. Unlike meningioma, mass was completely separated from dura mater without bone invasion. The mass was vascular, reddish, rubbery in consistency, and extra-axial with focal adhesion to arachnoid mater.

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  Fig. 3 Histopathologic findings stained hematoxylin and eosin, showed monomorphic cells with high cell density and delicate capillary blood vessels (×40) (A), clear perinuclear halo due to cytoplasmic clearing and bland cytology and mitotic count was 7 per 10 high power fields in the mostly active area (×400) (B). There were multifocal necrotic areas, microvascular proliferation and hyalinizing areas were noted in the part of tumor (×100) (C) and perivascular pseudorosettes found vaguely in the focal area (×100) (D).

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  Fig. 4 Immunohistochemistry findings showed weakly positive GFAP (×100) (A), S-100 protein multifocally expressed (×100) (B), EMA manifested as dot-like perinuclear cytoplasmic structures of a few tumor cells (×400) (C), and sparse OLIG2 expression (×100) (D).

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