PMC3505077_01
Contrast-enhanced coronal and axial T1-weighted magnetic resonance images showing the synchronous association of a left vestibular schwannoma and a right insular low grade glioma located in insular zone II-III according to the Berger-Sanai classification system (A and D). Five years later, magnetic resonance imaging documenting removal of vestibular schwannoma, as well as growth and possible high-grade transformation, because of the presence of focal areas of enhancement, of the right insular low-grade glioma (B and E). Postoperative final magnetic resonance imaging showing satisfactory removal of the insular oligodendroglioma (World Health Organization grade III), with only a small posteromedial residual tumor adjacent to the internal capsule, and stability of the left intrameatal vestibular schwannoma (C and F).
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The lesion appeared hyperintense on T2 and hypointense on T1 sequences, with homogeneous enhancement after gadolinium administration, suggesting a diagnosis of vestibular schwannoma (Figures 1 and 2). MRI features were suggestive of a low-grade glioma (Figures 1 and 2). She underwent surgery using a suboccipital retrosigmoid approach, which allowed near-total gross resection of the tumor, with only a small residual intrameatal component, decompression of the brainstem, and preservation of VII and VIII cranial nerve function (Figures 1 and 2). Postoperative MRI documented total gross resection of the lesion (Figures 1 and 2). The most recent follow-up MRI confirmed no regrowth of the small posteromedial remnant tumor (Figures 1 and 2).
Coronal T2-weighted and axial flair magnetic resonance images confirming the findings of Figure 1 (A-F).
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The lesion appeared hyperintense on T2 and hypointense on T1 sequences, with homogeneous enhancement after gadolinium administration, suggesting a diagnosis of vestibular schwannoma (Figures 1 and 2). MRI features were suggestive of a low-grade glioma (Figures 1 and 2). She underwent surgery using a suboccipital retrosigmoid approach, which allowed near-total gross resection of the tumor, with only a small residual intrameatal component, decompression of the brainstem, and preservation of VII and VIII cranial nerve function (Figures 1 and 2). Postoperative MRI documented total gross resection of the lesion (Figures 1 and 2). The most recent follow-up MRI confirmed no regrowth of the small posteromedial remnant tumor (Figures 1 and 2).
Loosely textured neoplasm made of spindle cells without significant cytological atypia seen on hematoxylin and eosin staining. Mitotic figures were not seen. The lesion was intensively stained by S100 protein (not shown). This image was taken from a small area of the tumor where the nuclei were aligned, suggesting initial formation of Verocay bodies. No true Verocay bodies were found since the lesion had mostly regressive areas. The morphology is consistent with a diagnosis of schwannoma (A). Hematoxylin and eosin staining showing an oligodendroglioma made of monomorphic cells with rounded nuclei and clear perinuclear halos. This image shows a small area of necrosis and newly formed blood vessels, consistent with early anaplastic transformation in the oligodendroglioma (B).
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The diagnosis was vestibular schwannoma (Figure 3A). The diagnosis was low-grade oligodendroglioma (World Health Organization grade II) with focal areas of grade III anaplasia (Figure 3B).