Intracranial Dural Metastasis of Ewing’s Sarcoma: a Case Report Eung Yeop Kim, MD1 Seung-Koo Lee, MD1 Dong Joon Kim, MD1 Jinna Kim, MD1 Kyu-Sung Lee, MD2 Woohee Jung, MD3 Dong Ik Kim, MD1 Index terms : Sarcoma, Ewing’s Neoplasm metastasis Meninges DOI:10.3348/kjr.2008.9.1.76 Korean J Radiol 2008;9:76-79 Received May 24, 2006; accepted after revision November 14, 2006. 1Department of Radiology, the Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul 120-752, Korea; 2Department of Neurosurgery, Yonsei University College of Medicine, Seoul 120-752, Korea; 3Department of Pathology, Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul 120-752, Korea Address reprint requests to: Eung Yeop Kim, MD, Department of Radiology and the Research Institute of Radiological Sciences, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea. Tel. (822) 2228-2377 Fax. (822) 393-3035 e-mail: eungykim@yuhs.ac 76 Although intracranial dural metastasis of Ewing’s sarcoma is a very rare finding, its imaging characteristics are similar to those of its primary form in the central nervous system. Thus, this tumor must be considered in the differential diagnosis of extra-axial dural masses. E body, but it is most commonly observed in the long bones of the arms wing’s sarcoma is a malignant bone tumor that can occur anywhere in the and legs, the pelvis and in the chest. The predominant sites of metastasis include the lung (38%), bone (including the spine; 31%), and the bone marrow (11%) (1). Metastasis of Ewing’s sarcoma to the central nervous system (CNS) is relatively rare, and most of the previous reports have demonstrated involvement of the bony calvarium or brain parenchyma (2). We describe here the imaging findings of dural metastasis of Ewing’s sarcoma, and these imaging findings have not been previously reported on in the medical literature. CASE REPORT A 21-year-old woman presented in 1996 with right arm pain and weakness. She underwent total laminectomy at C7-T1 with gross total removal of the intradural tumor and partial removal of the extradural tumor. The pathologic diagnosis was Ewing’s sarcoma, and it showed the expression of MIC-2 antigen according to immunohistochemistry. The patient presented with recurrent right side weakness the following year and so she underwent resection of the recurrent mass followed by chemotherapy and radiation treatment. No metastatic lesion was found at the time of the first or second operation. The patient was healthy until August 2004 when she complained of headache. No recurrent tumor was found in the spine at that time. In March 2005, she presented with slowly progressing left side weakness and paresthesia. MRI was performed at 3.0 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. Several spots of dark signal-intensity were noted within the mass on MRI, suggesting the presence of hypervascularity, hemorrhage or calcifications. Edema was noted in the pons and cerebellum adjacent to the mass. Noncontrast CT showed a spot of subtle high attenuation within the mass, suggesting the possibility of calcifica- tion or hemorrhage (Fig. 1C). CT also demonstrated a high-attenuation curvilinear area near the cerebellum, and this showed low signal intensity on T2-weighted Korean J Radiol 9(1), February 2008