Small round blue cell tumors are rare, aggressive tumors that are uncommon in pediatric females and are uncommonly found outside the abdomen. A 9-year-old female with intracranial left frontal high grade small round blue cell sarcoma underwent left frontal craniotomy with gross total resection. The lesion was highly vascularized, continuously bled during surgery, and a large branch of the anterior cerebral artery had to be coagulated. A month later, the patient began proton beam radiation therapy; after 2 weeks of treatment, she noticed declining vision and memory. Exam showed a visual acuity of 20/200 in both eyes, moderate dyschromatopsia, bilateral central scotoma, and bilateral temporal optic nerve atrophy. Potential differential diagnoses for this case include vascular insult to the anterior cerebral arteries and their branches which supply the optic chiasm, elevated intracranial pressure prior to resection, side effects of radiation therapy, or malignancy recurrence and/or infiltration.