Primary Ewing sarcoma of the cavernous sinus

Introduction: Ewing sarcoma (ES) is a part of a larger family of round blue-cell tumors that occasionally manifest as osseous or extraosseous lesions adjacent to or within the central nervous system (CNS). Although a large body of literature exists on ES of bone, data are lacking on tumors with cranial or spinal components that affect the CNS. Moreover, primary intracranial ES has been uncommonly reported, and its location in the cavernous sinus is extremely rare, with only a few cases reported in literature. Method: We describe a case of a 15-year-old boy who presented initially with a seizure along with acute abducens, trochlear, and oculomotor nerve pareses. Magnetic resonance imaging (MRI) revealed a cavernous sinus mass. Given the rapid growth and aggressive nature of the mass, a biopsy of the lesion was performed. Microscopic examination of the specimen showed immunohistological features consistent with ES. The patient was treated with multi-agent chemotherapy and fractionated radiation therapy. Result: Clinical assessment 7 months after completion of chemotherapy and 4 months after completion of radiotherapy revealed that the patient’s ocular motility and alignment had improved significantly, and MRI showed almost complete disappearance of the tumor. Conclusion: This is one of only six cases of extraosseous primary intracranial ES of the cavernous sinus reported in literature to date. The availability of multi-agent chemotherapy and fractionated radiation therapy in this patient resulted in his marked clinical and imaging improvement. It remains to be seen if this therapy will result in long-term control or cure of the lesion in our patient. In the meantime, increasing awareness and identification of children primary intracranial ES will hopefully allow a better understanding of the molecular biology of this tumor and the development of standardized treatment regimens.