J Korean Soc Radiol.  2016 Jan;74(1):61-65. 10.3348/jksr.2016.74.1.61.

Cerebellar Clear Cell Ependymoma in a 10-Year-Old Girl

• Thinzar AN
• Park J
• Moon A
• Hwang SC
• Hong HS
• Lee AL
• Chang KH
• Kim HK
• Chin S

• KMID: 2150464
• DOI: http://doi.org/10.3348/jksr.2016.74.1.61

Abstract

Clear cell ependymoma (CCE) is a histological rare variant (1-5%) of ependymoma, which is distinguished from other histological subtypes by the presence of fusiform cells arrayed radially around small blood vessels. These alleged perivascular pseudorosettes are significant characteristic features of ependymomas. About 95% of infratentorial ependymomas are found in the fourth ventricle and the remainder occurs as cerebellopontine angle lesions. In previous reports, the cerebellum is found to be a rare location for ependymoma. In this study we report one case of CCE originating from the cerebellar hemisphere, showing unusual morphology on 3T MRI.

MeSH Terms

Blood Vessels
Cerebellopontine Angle
Cerebellum
Child*
Ependymoma*
Female*
Fourth Ventricle
Humans
Magnetic Resonance Imaging

Figure

• 

  Fig. 1 Precontrast CT (A) and postcontrast CT (B) show cystic mass in the left cerebellar hemisphere with thin enhancing wall without gross hemorrhage or calcification. Axial T2-weighted (C) and T2 fluid attenuation inversion recovery (D) 3T MR images show cystic mass in the left cerebellar hemisphere with thin high intensity wall. Axial and sagittal contrast-enhanced T1-weighted images (E, F) show thin marginal enhancement without definite mural nodule. Diffusion weighted image (G) shows no restricted diffusion with high apparent diffusion coefficient value (H).

• 

  Fig. 2 Photomicrographs of the excised cerebellar mass. A. Photomicrographs show tumor cells arranged in sheets intersected by small blood vessels. Discrete margin is noted in relation to adjacent brain (H&E, × 100). B. Tumor cells show rounded nuclei and abundant surrounding clear cytoplasm. Perivascular pseudorosettes are subtle (H&E, × 400). C. Tumor shows positivity for glial fibrillary acidic protein in the fibrillary matrix (× 200). D. Electron photomicrograph shows intracytoplasmic lumina with some microvilli (× 4000). H&E = hematoxylin and eosin

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