A right-handed adult with a history of an unruptured arteriovenous malformation (AVM) presents with increasing frequency and intensity of partial seizures despite maximum medical management. Magnetic resonance imaging (MRI) (Fig. 1A and 1B) shows a 2 × 4.7 cm AVM in the right frontal lobe just anterior to the motor cortex with deep venous drainage to the right lateral ventricle and deep middle cerebral vein (Spetzler-Martin grade 4). The patient elects for embolization followed by stereotactic radiosurgery (SRS). Partial embolization by SRS is performed, with 16 Gy delivered to the margin of the residual nidus (Fig. 2). Six months post-SRS, the patient is asymptomatic with minimal changes on MRI (Fig. 1C). However, 11 months post-SRS, the patient presents with new-onset severe headaches, multiple seizures, and progressive left-sided weakness. MRI (Fig. 1D) shows more conspicuous AVM flow-voids, substantial vasogenic edema, a 7 mm midline shift, and thrombosis of a large cortical draining vessel.