extraskeletal ewing 's sarcoma is a rare , round - cell , malignant tumor of uncharacterized mesenchymal cell origin that manifests most commonly in the paravertebral and intercostal regions . it occurs predominantly in adolescents and young adults between the ages of 10 and 30 years and it follows an aggressive course with a high rate of recurrence . it was first recognized by tefft et al in 19691 ) when he reported four patients with paravertebral soft tissue tumors that histologically resembled ewing 's sarcoma . in 1975 , angervall and enzinger2 ) reviewed 39 patients with malignant soft tissue paravertebral tumors not arising from bone but having similar morphologic characteristics to osseous ewing 's sarcoma . the head and neck region is an unusual primary site for this type of tumor and , according to chao et al.3 ) , there were only five out of 118 cases of extraskeletal ewing 's sarcoma located in the head and neck region . 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 . 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 histological image of extraskeletal ewing 's sarcoma is a small , blue , round cell with a scanty cytoplasm and it is often confused with other small round - cell tumors . nearly all of the tumors within the ewing 's sarcoma family of tumors express the mic2 gene product , cd99 , on their cell membranes . lymphoblastic lymphoma and rhabdomyosarcoma can be excluded by negative staining for leukocyte common antigen , cd30 , myosin , actin , and myoglobulin . neuroblastoma can be excluded by negative staining for neurofilament , neuron - specific enolase , and the s-100 protein5 , 6 ) . our patient was diagnosed with extraskeletal ewing 's sarcoma based on the results of extensive immunohistochemical staining as described above . our patient 's case of extraskeletal ewing 's sarcoma developed in the parapharynx and resulted in gradual visual loss due to tumor thrombosis . the diagnosis of extraskeletal ewing 's sarcoma was delayed in our patient because he was quite older than most patients with extraskeletal ewing 's sarcoma . in addition , the patient 's case of extraskeletal ewing 's sarcoma was accompanied by rectal cancer . however , in comparison to the poor clinical outcome typically associated with extraskeletal ewing 's sarcoma , this patient demonstrated durable remission after radiation and combination chemotherapy , but his visual acuity did not improve . examination of the patient 's eye revealed bilateral optic disc swelling ( papilledema ) and atropy of the optic nerve . the patient 's visual loss might have been due to the tumor thrombosis involving the superior sagittal sinus , straight sinus , transverse sinus , sigmoid sinus , and internal jugular vein . papilledema might have been caused by elevated intracrainal pressure due to the tumor thrombosis of the dural venous sinus . with unremitting papilledema , the maintenance of optic nerve atropy resulted in blurred vision . according to peter et al7 ) , when 77 patients with cerebral venous thrombosis were followed up for a mean of 77.8 months , two patients who initially presented with isolated intracranial hypertension had blindness due to optic atrophy . our case serves as a good example of gradual visual loss due to extraskeletal ewing 's sarcoma of the parapharynx . early awareness and wide resection followed by chemotherapy and radiotherapy might improve the long - term survival of patients with extraskeletal ewing 's sarcoma . the rate of survival in extraskeletal ewing 's sarcoma has improved from 8% to nearly 65% in patients with extremity lesions and to 83% in patients with truncal lesions , and the prognosis is now approaching that of skeletal ewing 's tumors8 ) . further research is needed to improve the therapeutic strategy according to the proper clinical course .
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 .