PMC5223764_01
Axial T1-weighted MRI (A) shows an extra-axial mass lesion under the left cerebellar tentorium one month before admission. Axial CT (B), T1-weighted MRI (C) and Coronal Gd-enhanced T1-weighted MRI (D) on admission show the enlarged mass lesion with niveau formation at one month later. MRI: magnetic resonance imaging, CT: computed tomography.
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An 82-year-old women came to the department because magnetic resonance imaging (MRI), followed up every one year for asymptomatic cerebral infarction, showed mass lesion under the left cerebellar tentorium (Fig. 1). It did not show enhancement after gadolinium administration (Fig. 1). 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT), chest and abdominal enhanced CT did not detect any malignant lesion such as an extracranial malignant melanoma (Fig. 2).
Whole body FDG-PET/CT (A) on admission shows no malignant lesions such as extracranial malignant melanoma. FDG-PET/CT (B) at 12 months after the surgery shows FDG uptake in multiple metastatic lesions. FDG-PET/CT: 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography.
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It did not show enhancement after gadolinium administration (Fig. 1). 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT), chest and abdominal enhanced CT did not detect any malignant lesion such as an extracranial malignant melanoma (Fig. 2). Therefore, FDG-PET/CT, chest and abdominal CT for a whole body examination was performed and showed multiple metastases in the left neck, the right latissimus dorsi muscle, the right collarbone, the liver, multiple vertebral bodies and the left thigh bone (Fig. 2).
Intraoperative image (A) shows the black colored tumor on the left cerebellar tentorium. Photomicrographs. The tumor cells arranged in fascicles intersperse with melanin-containing cells (B, H&E, x200). The tumor cells are positive for Melan-A (C, x400). The MIB-1 (Ki-67) staining index is approximately 8% (D, x400).
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A black solid and encapsulated nodular tumor was found under the left cerebellar tentorium and appeared to originate from the pia mater of the cerebellum (Fig. 3). The MIB-1 (Ki-67) staining index was approximately 8% (Fig. 3).