PMC4508720_01
A, B: shows sagittal and coronal CT views demonstrating acute extratumoral hemorrhage between the cisterna magna and the atlas. C, D: represents sagittal and axial views of a non-enhancing fourth ventricle tumor on T1-weighted contrast MRI sequences. CT: computed tomography, MRI: magnetic resonance imaging.
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F1
Unenhanced computed tomography (CT) scan demonstrate a well-circumscribed isointense mass located in the inferior portion of the fourth ventricle with a spontaneously hyperdense acute extratumoral hemorrhage in the cistern magna (Fig. 1). T2-weighted images, involving the floor of the fourth ventricle extending caudally into cervical spinal canal via foramen magnum measuring approximately 30 mm in diameter (Fig. 1). The patient was operated immediately through a midline suboccipitalcraniectomy and a velotonsilar approach. The cistern magna was opened and hemorrhagic CSF under high pressure was aspirated sequentially.
A: intraoperative photo demonstrate subarachnoid hemorrhage (CR, cranial). B: white asterisk shows large blood clot, yellow revealed fourth ventricle tumor and the black asterisk mark the brain stem (CA, caudal). C: represents tumor site of hemorrhage. D: shows complete tumor excision and the fourth ventricle floor.
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F2
A large blood clot was removed and a firm, well delimitated, yellow-white partially cyst-lobulated, macroscopically hypovascular lesion was recognized and completely excised, which was attached to the right lateral recess and the floor of the fourth ventricle previous desvascularization from small branches of the right posteroinferior cerebellar artery (Fig. 2).
A: represents clusters of isomorphic nuclei embedded in a dense fibrillary matrix of glial processes and an ependymal pseudorosette (H&E 10x). B: shows immunoreactivity for GFAP (40x). C: revealed Ki67 label index below 2% (40x). D: demonstrates some lobular architecture, in an hypocellular area in a highly fibrillary background area with calcifications (H&E 10x). H&E: hematoxylin-eosin, GFAP: glial fibrillary acidic protein.
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F3
Intra and postoperative immunohistopathological examination revealed a SE (Fig. 3).
A, B: shows sagittal and coronal postoperative CT views demonstrating surgical approach and hemorrhage resolution. C, D: represents T1-weighted contrast MRI sagittal and axial views demonstrating complete tumoral resection. CT: computed tomography, MRI: magnetic resonance imaging.
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F4
A 10-month postoperative MRI study confirmed a complete resection of the tumor with normal CSF circulation (Fig. 4).