A 49-year-old man presented with a six-month history of diplopia and mild headache. The diplopia was gradually aggravated and blindness developed two months before he visited our hospital. Ophthalmologic examination revealed bilateral papilledema and atropy of the optic nerve. MRI examination showed marked enhancement of the tumor thrombosis involving the superior sagittal sinus, straight sinus, transverse sinus, sigmoid sinus, and internal jugular vein (
Figure 1). Additional PET-CT examination showed hypermetabolic lesion of the neck, mediastinal lymph node, lung and rectum in addition to lesions of the head and neck (
Figure 2). The patient underwent a gun biopsy of the internal jugular vein thrombosis and a sigmoidoscopic biopsy of the rectal mass. Histopathological examination of the internal jugular vein thrombosis showed a small, round-cell malignant tumor with extensive geographic necrosis (
Figure 3). Immunohistochemical studies showed that the tumor cells stained positive for CD99, Vimentin, and CD56, but stained negative for S-100, Desmin, Chromogranin, and leukocyte common antigen (
Figure 4). Based on MRI and PET-CT findings, the histological pattern, and the results of the immunohistochemical studies, the final diagnosis was extraskeletal Ewing's sarcoma of the parapharynx with pulmonary metastasis. Histopathological examination of an ulcerative rectal mass showed well- differentiated adenocarcinoma and, therefore, the patient was also diagnosed with rectal cancer (
Figure 5). The patient was treated with palliative radiotherapy on the parapharynx and systemic chemotherapy with cyclophosphamide, adriamycin and vincristine, after which Grade IV febrile neutropenia and Grade III diarrhea developed. He could not receive further treatment due to poor tolerance and the toxicity of the treatment. A follow-up examination with PET after 20 months showed that the hypermetabolic lesions of the head, neck and chest disappeared, but no significant interval change was observed in the hypermetabolic lesion of the rectum (
Figure 6). The patient's visual acuity, however, did not improve.