PMC4253034_01
Tanycytic ependymoma. (a) T2-axial MRI showing a hyperintense lesion in the left CPA with extension into the internal auditory canal. The same lesion in axial (b) and coronal (c) views on T1-weighted MRIs. Postgadolinium enhancement showing a homogenously enhancing lesion extending from the ICA into the left CPA. There are clear mass effect shown on the brainstem and absence of hydrocephalus
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F1
A magnetic resonace imaging (MRI) of the head showed a 3 x 3.5 cm homogenous contrast-enhancing CPA mass extending into the internal auditory canal with resultant mass effect and edema involving the cerebellum, pons, and medulla [Figure 1].
Histology provided accurate diagnosis of tanycytic ependymoma. (a) Permanent sections of the tumor show a piloid to spindled appearance with vague perivascular pseudorosettes (H and E, original magnification x200). (b) Diffuse positive staining for GFAP (GFAP IHC; original magnification x100). (c) Dot- and ring-like perinuclear staining for EMA (EMA IHC; original magnification x400)
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F2
Overall histologic appearance was most consistent with a tanycytic ependymoma (World Health Organization [WHO] grade II), and this finding was supported by immunohistochemical and special stains [Figure 2].