J Korean Soc Radiol.  2013 Jan;68(1):5-8.

Intracranial Extra-Axial Ependymoma in the Ambient Cistern That Initially Presented as Calcification: A Report of Case

• Seo GY
• Byun JS
• Kim JK
• Kwon JT
• Park ES
• Jung YY

Abstract

Ependymomas usually occur in intraventricular or intraspinal locations. Intracranial extraaxial ependymomas (IEAEs) are very rare. Here, we present an unusual case of an IEAE in 25-year-old man. The patient experienced head trauma two and half years prior to presentation, at which time brain computed tomography (CT) showed only a dense calcification in the left ambient cistern. After two and a half years, follow up brain CT and magnetic resonance imaging depicted interval growth of a calcified mass with cystic change. The tumor was successfully treated surgically, and the pathologic examination confirmed ependymoma.

MeSH Terms

Brain
Craniocerebral Trauma
Ependymoma
Follow-Up Studies
Humans
Magnetic Resonance Imaging

Figure

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  Fig. 1 A 25-year-old man with an intracranial extraaxial ependymoma in left ambient cistern. A. Nonenhanced CT shows a dense, large (1.2 × 0.8 cm) calcification in the left ambient cistern. B, C. Nonenhanced CT shows a lobulated (2.5 × 2.0 cm) cystic mass (B) with fragmented calcifications (C) in the left ambient cistern. D-G. An axial T1 weighted image shows a lobulated hypointense mass with a peripheral thin solid component in the left ambient cistern (D). An axial T2 weighted image shows a hyperintense mass with low signal multiple dot calcifications (E). Axial (F) and sagittal (G) gadolinium enhanced T1-weighted images show heterogeneous enhancement in the solid component of the mass. H, I. A low-power photomicrograph (hematoxylin and eosin, × 40) shows that the tumor has moderate cellularity and numerous calcifications (H). A high-power photomicrograph (hematoxylin and eosin, × 400) shows sheets of spindled or ephithelioid cells with round to oval nuclei in the tumor. A nuclear free zone is seen around the central blood vessel (pseudorosette; white arrows) (I). J, K. Immunohistochemical examination of the tumor reveals that S-100 (J) and glial fibrillary acid protein (K) stains are positive (× 200).

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