Primary Intracranial Ewing Sarcoma Arising from the Cavernous Sinus in an Older Woman with a History of Intensive Breast Cancer Treatment: A Case Report

A 72-year-old woman with a history of breast cancer presented with left oculomotor nerve palsy. Magnetic resonance imaging revealed a progressive mass lesion in the cavernous sinus. Initially, Tolosa-Hunt syndrome and metastatic brain tumor from breast cancer were suspected; however, radiological differentiation proved challenging. Pathological examination confirmed the diagnosis of primary intracranial Ewing sarcoma. The tumor exhibited progressive growth, and Gamma Knife radiosurgery was performed. After treatment, tumor shrinkage and symptomatic improvement were observed. Ewing sarcoma typically occurs in children and young adults; however, the safety and efficacy of chemotherapy in older populations remain largely unstudied. In this older patient, the rare location of the tumor within the cavernous sinus posed challenges to surgical resection. Chemotherapy was administered at a reduced dose of 50%, with limited side effects. After 7 cycles of chemotherapy, tumor showed further shrinkage, and no recurrence was observed. This case demonstrates that, even in rare tumors with unestablished chemotherapy protocols for older patients, satisfactory outcomes can be achieved with accurate pathological diagnosis and a multidisciplinary treatment approach.