1190. Pure Arterial Malformations: Rare, Benign Vascular Lesion or Marker of Insidious Cerebral Pathology?

Authors: Christopher P. Carroll, MD; Vyshak Chandra, MD; John Mayfield, BS; Devan Patel, BS; Alexis Simpkins, MD, PhD; Brian Hoh, MD (Gainesville, FL)

Introduction: Rare cerebrovascular malformations consisting of bundled, tortuous arteries without associated venous drainage have been sporadically described. These pure arterial malformations (PAM), which may be misdiagnosed as an arteriovenous malformation (AVM), are often left untreated due to limited case reports and series reporting a benign course. Feliciano et al reported a case of PAM-associated MCA occlusion and intracranial hemorrhage (ICH), hypothesizing a relationship between the MCA occlusion, PAM, dysplastic collateralization, and ICH. Herein we report the clinical and radiographic presentation of a second PAM associated with ICH and ipsilateral MCAO with dysplastic collateralization. Methods: Retrospective case review and systematic literature review. Results: A 63-year-old female presented after being found down with left-sided weakness and urinary incontinence. She presented with a Glasgow Coma Scale of 14 with left facial weakness, left hemiparesis, and left hemianesthesia. Non-contrast CT head demonstrated a 13cc ICH of the right basal ganglia/internal capsule. CT angiogram identified amorphous vascular enhancement adjacent to the hemorrhage favored to represent an AVM as well as aneurysm of the left superior hypophyseal artery, anterior communicating artery, and right ACA remote from the ICH. The patient underwent a cerebral angiogram demonstrating a PAM of the right MCA and associated MCA occlusion with dysplastic lenticulostriate collateralization in the hemorrhage territory. The patient was managed conservatively and discharged to inpatient rehab on hospital day 5. Conclusion: PAMs are a rare cerebrovascular malformation that may be misdiagnosed as an AVM. This case and that reported by Feliciano et al demonstrate PAMs in association with a constellation of arterial occlusion and irregular collateral revascularization similar to that seen in Moya-Moya disease. The natural history of PAMs is poorly characterized and their association with secondary vascular dysplasia warrants long-term follow up. While PAMs themselves may indeed be benign, they may herald more insidious associated pathology.