PMC4533488_01
T1-weighted (upper left), T2-weighted (upper center), fluid-attenuated inversion recovery (upper right), and T1-weighted with gadolinium (lower row) magnetic resonance images at the initial presentation showing a large ring-enhanced cystic lesion in the right parasellar region, and a heterogeneously enhanced lesion extending to the posterior cranial fossa with displacement of brain stem structures and the region of the third ventricle.
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F1
M4). Computed tomography revealed an acute epidural hematoma in the left convexity and a mass lesion in the right middle cranial fossa extending to the cerebellopontine angle. Magnetic resonance imaging showed a tumor (50 x 37 x 40 mm) in the middle cranial fossa extending to the cerebellopontine angle, containing multiple intratumoral cysts, with heterogeneous enhancement after gadolinium injection (Fig. 1).
Preoperative cerebral digital subtraction angiogram of the posterior circulation indicating separation of the posterior cerebral artery and superior cerebellar artery by the mass lesion (white arrowheads).
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F2
The lesion was avascular (Fig. 2).
T1-weighted with gadolinium magnetic resonance images after the first (A) and second (B) operations showing tumor remains in the oculomotor cistern.
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F3
The caudal part of the tumor was not visible and could not be resected through this approach (Fig. 3A). The tumor was subtotally removed (Fig. 3B).
Photomicrograph of the resected lesion demonstrating a cellular pattern consistent with schwannoma. Hematoxylin and eosin stain, original magnification x40.
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F4
Histological examination confirmed a diagnosis of schwannoma (Fig. 4).
A: Intraoperative photograph showing the tumor and the superior cerebellar artery (SCA), with the oculomotor cistern filled with tumor. B: Drawing showing the anatomical relationship between the tumor and the posterior cerebral artery (PCA), SCA, and oculomotor nerve. The oculomotor nerve is spread and involved in the tumor. The PCA is displaced superiorly and the SCA is displaced inferiorly.
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F5
Six weeks later, second operation to remove the remnant tumor was performed through the right subtemporal route (Fig. 5).