PMC7749961_01
Preoperative noncontrasted brain computer tomography-scan demonstrated a hypodense cystic lesion on the right middle cranial fossa at the base of the skull. The lesion extends upward contributing to a mass effect on the contralateral hemisphere. Notice the contralateral ventricular dilatation.
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F1
Preoperative brain computer tomography (CT) scan demonstrated a cystic lesion at the right middle fossa on base of the skull [Figure 1].
Three views T1 ([a] Axial, [b] Coronal, [c] Sagittal) Contrasted magnetic resonance imaging showing an extra-axial cystic lesion attached to the skull at the right cavernous sinus associated with significant mass-effect, compression of the brain parenchyma, vasogenic edema in the right temporal and parietal lobes, ventricular compression and subfalcine herniation with active hydrocephalus particularly in the left lateral ventricle. The tumor exhibits a close relation to the right Meckel's cave and compresses it.
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F2
Brain magnetic resonance imaging (MRI) showed a right temporal extra-axial cystic lesion attached to the skull base, measuring 7 x 6 cm at maximum diameter [Figure 2].
Histopathological findings. (a) Hematoxylin and Eosin stain, showing spindle cells arranged in fascicles in hypercellular and hypocellular areas, with mild nuclear atypia without any signs of active mitosis. Thin-walled blood vessels were noted. (b) Immunohistochemical staining revealed diffuse positive reactions of cells toward the presence of the S100 protein.
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F3
Both microscopic and immunohistochemial characteristics of the lesion were consistent with ancient schwannoma [Figure 3].
Postoperative axial, T1, contrasted magnetic resonance imaging illustrated postoperative leukomalacia, no residual tumor and the absence of a mass effect in terms of midline shifts or ventricular compression. Postoperative subgaleal collections are noted at the site of surgery.
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F4
MRI follow-up showed no signs of tumor recurrence [Figure 4].