Radiation necrosis within the left medial temporal lobe in a patient treated with proton therapy for a skull base chondrosarcoma. T1-weighted axial postcontrast MRI (A) shows a lacy pattern of enhancement within the left medial temporal lobe (arrow). T2-weighted MRI (B) shows T2 hyperintensity extending posteriorly in the left temporal lobe (arrow), consistent with vasogenic edema. The patient also experienced blindness in the left eye due to radiation injury to the left optic nerve.
