Extraskeletal Ewing's sarcoma is rarely found in the head and neck regions. We report an unusual case of extraskeletal Ewing's Sarcoma of the parapharynx region in a 49-year-old man who presented with blindness. MRI examination showed marked enhancement of tumor thrombosis involving the superior sagittal sinus, straight sinus, transverse sinus, sigmoid sinus, and internal jugular vein. The final diagnosis was extraskeletal Ewing's sarcoma after biopsy of the internal jugular vein thrombosis by histopathological evaluation and immunohistochemical assay. In addition, the patient was diagnosed as having adenocarcinoma of the rectum by biopsy of the rectal mass. The patient was treated with systemic chemotherapy and showed improved response with durable remission. The patient's visual acuity, however, did not improve.