PMC2627171_01
The T2-weighted (A) and postcontrast T1-weighted images (B) show a mass in the right cerebellopontine angle cistern with extension into the ipsilateral Meckel's cave. The mass shows a slightly heterogeneous lobulated contour with similar or slightly higher signal intensity than the cortex on the T2-weighted images, with heterogeneous enhancement. Edema is noted in the pons and cerebellum adjacent to the mass. Noncontrast CT shows spots of subtle high-attenuation within the mass (arrows), suggesting the possibility of calcification or hemorrhage. Also seen is a high-attenuation curvilinear area between the mass and the cerebellum (curved arrow), which was determined to be fibrosis on the pathologic examination (C). The ipsilateral internal auditory canal and petrous bone are free of tumor on both the CT and MRI (A-C). Immunohistochemistry demonstrates the MIC-2 antigen expression (D). Follow-up MRI reveals a new enhancing lesion abutting the anterior falx cerebri and left fovea ethmoidalis, and this suggests metastasis (E).
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F1
T, and this showed a mass in the right cerebellopontine angle cistern with extension into the ipsilateral Meckel's cave (Figs. 1A, B). The mass showed a slightly heterogeneous lobulated contour with similar or slightly higher signal intensity than the cortex on the T2-weighted images, with heterogeneous enhancement. CT showed a spot of subtle high attenuation within the mass, suggesting the possibility of calcification or hemorrhage (Fig. 1C). CT also demonstrated a high-attenuation curvilinear area near the cerebellum, and this showed low signal intensity on T2-weighted imaging and no enhancement (Fig. 1A, B). The ipsilateral internal auditory canal and petrous bone were free of tumor on both CT and MRI (Fig. 1A-C). Catheter angiography showed no blood supply from the meningeal arteries. The pathologic diagnosis was a metastatic Ewing's sarcoma with a MIC-2 antigen expression (Fig. 1D). MRI revealed a new enhancing lesion abutting the anterior falx cerebri, and left fovea ethmoidalis was also noted (Fig. 1E).