PMC4844666_01
Serial T2-weighted magnetic resonance imaging (MRI). (A) Previous follow-up MRI shows no abnormality in the cerebellum. (B) MRI in July 2012 shows a small, high-intensity area in the right cerebellar hemisphere (arrowhead). (C) MRI 3 months after detection of the abnormality shows expansion of the high-intensity area in the right cerebellar hemisphere (arrowhead).
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Although previous MRI showed no abnormality in the cerebellum, MRI in July 2012 showed a small abnormality in the left cerebellar hemisphere (Fig. 1A,B). Repeated MRI in October 2012 showed growth of the abnormal signal, although clinical symptoms remained absent (Fig. 1C).
Serial gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI). (A) MRI performed 3 months after detection of the abnormality shows homogeneous nodular enhancement. (B) MRI performed 5 months after detection of abnormality shows growth of the enhanced lesion. (C) MRI performed 6 months postoperatively shows an irregular, ring-like enhancing lesion, indicating local recurrence.
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The lesion showed homogeneous nodular enhancement on gadolinium contrast-enhanced T1-weighted imaging (Fig. 2A), and metastatic cerebellar tumor was suspected. Repeated MRI in December 2012 showed growth of the enhanced mass lesion, and by this time the patient had developed dysarthria and floating sensation (Fig. 2B). The patient subsequently underwent gamma knife radiosurgery (26 Gy) and chemotherapy with temozolomide, but local recurrence was observed 6 months postoperatively (Fig. 2C).
Photomicrographs of surgical specimens. (A, B) Tumor cells show eosinophilic cytoplasm and processes with irregular and hyperchromatic nuclei. Although vascular endothelial proliferation is observed, micronecrosis is not detected. Hematoxylin and eosin stain. (C) Immunohistochemical staining for glial fibrillary acidic protein shows strongly positive tumor cells. (D) Immunohistochemical staining for MIB-1 shows that approximately 20% of cells are positive.
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Immunohistochemical staining was positive for glial fibrillary acidic protein, and the MIB-1 labeling index was approximately 20% (Fig. 3).