PMC5379781_01
(a) CECT showing a heterogeneously enhancing extra-axial tumor in the right CPA cistern; (b) MRI T1W shows an isointense lesion in the right CPA, note the gross distortion of the pons. The tumor measured 4x4.5x5.5 cm; (c) On T2W, the lesion is hyperintense, with clefts of CSF seen adjacent to the cerebellum and the brainstem; (d) T1W post-gadolinium contrast shows bright contrast enhancement with an intrametal extension; (e) Coronal T1W post-gadolinium contrast shows the tumor causing gross brainstem distortion, with the rostral extent reaching the tentorium with no hydrocephalus; (f) postoperative CECT, 3 weeks after surgery shows no residual tumor. Postoperative craniectomy defect and a pseudomeningocoele is seen
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F1
Magnetic resonance imaging (MRI) with gadolinium contrast [Figure 1b-1e] showed an extra-axial lesion in the right cerebellopontine angle measuring 4x4.5x5.5 cm, which was isointense on Contrast-enhanced CT scan [Figure 1f] showed complete tumor excision with hydrocephalus and subgaleal collection of CSF at the surgical site.
(a) Hematoxylin and eosin-stained section showed a cellular tumor with round nuclei, coarse chromatin, small to conspicuous nucleoli and moderate amount of eosinophilic cytoplasm. Arrow points to a cell with tailing of the cytoplasm (b) Myogenin immunohistochemistry showed diffuse strong nuclear staining (c and d) Diffuse strong cytoplasmic staining for desmin and vimentin, respectively
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F2
Histopathological examination of surgical specimen [Figure 2a] showed a cellular tumor with mild to moderately pleomorphic round nuclei, coarse chromatin, and conspicuous nucleoli, with moderate to abundant eosinophilic cytoplasm with suggestion of cytoplasmic striations in places. The tumor cells were immunoreactive for desmin, vimentin, and myogenin [Figure 2b-2d].