Preoperative embolization of a juvenile nasopharyngeal angiofibroma (JNA) using ethyl vinyl alcohol (EVOH) is an effective adjunctive treatment prior to surgical resection. While liquid embolic agents are safe to use, we present a unique case involving the migration of EVOH into the left middle cerebral artery (MCA) through an external carotid artery-internal carotid artery (ECA-ICA) collateral during preoperative embolization using a dual-lumen balloon catheter. A 16-year-old male presented with left-sided nasal congestion, new nasal intonation in voice, and epistaxis. CT imaging showed a hypervascular mass centered within the left posterior nasal cavity and nasopharynx with expansion of the ipsilateral sphenopalatine foramen. A JNA was diagnosed, and preoperative embolization was performed prior to surgical resection. During the embolization procedure, EVOH migrated into the intracranial circulation through a hypertrophied ECA-ICA collateral. Angiography confirmed embolic material at the left MCA bifurcation. The embolic material was successfully removed using a balloon guide catheter and stentriever. This case is presented to highlight potential complications and rescue techniques used in the setting of non-target embolization occurring during JNA embolization.