Hindawi Publishing Corporation Case Reports in Neurological Medicine Volume 2013, Article ID 631028, 8 pages http://dx.doi.org/10.1155/2013/631028 Case Report Hypofractionated Stereotactic Radiosurgery in a Large Bilateral Thalamic and Basal Ganglia Arteriovenous Malformation Janet Lee, 1 Tomoko Tanaka, 1 Steven Westgate, 2 Ashish Nanda, 3 Marshall Cress, 1 and N. Scott Litofsky 1 1 Division of Neurological Surgery, University of Missouri-Columbia School of Medicine, One Hospital Drive, MC 321, Columbia, MO 65212, USA 2 Division of Radiation Oncology, University of Missouri-Columbia School of Medicine, Columbia, MO 65212, USA 3 Department of Neurology, University of Missouri-Columbia School of Medicine, Columbia, MO 65212, USA Correspondence should be addressed to N. Scott Litofsky; litofskyn@health.missouri.edu Received 24 August 2013; Accepted 3 October 2013 Academic Editors: F. Micheli, Y. Wakabayashi, and J. B. White Copyright © 2013 Janet Lee et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose. Arteriovenous malformations (AVMs) in the basal ganglia and thalamus have a more aggressive natural history with a higher morbidity and mortality than AVMs in other locations. Optimal treatment—complete obliteration without new neurological defcits—is ofen challenging. We present a patient with a large bilateral basal ganglia and thalamic AVM successfully treated with hypofractionated stereotactic radiosurgery (HFSRS) with intensity modulated radiotherapy (IMRT). Methods. Te patient was treated with hypofractionated stereotactic radiosurgery to 30 Gy at margin in 5 fractions of 9 static felds with a minimultileaf collimator and intensity modulated radiotherapy. Results. At 10 months following treatment, digital subtraction angiography showed complete obliteration of the AVM. Conclusions. Large bilateral thalamic and basal ganglia AVMs can be successfully treated with complete obliteration by HFSRS with IMRT with relatively limited toxicity. Appropriate caution is recommended. 1. Introduction Arteriovenous malformations (AVMs) in the basal ganglia and thalamus comprise a small percentage of all AVMs [1–4]. Tese deep AVMs have a more aggressive natural history with a higher morbidity and mortality than AVMs in other locations [5]. Bilateral basal ganglia and thalamic AVMs are extremely rare. Te majority of patients harboring these lesions present with hemorrhage and serious neurologic sequela. Optimal treatment—complete obliteration without new neurological defcits—is ofen challenging. Stereotactic radiosurgery (SRS) is generally accepted as the frst option in treatment [3, 5, 6]. In this report, we present a patient with a large bilateral basal ganglia and thalamic AVM successfully treated with hypofractionated stereotactic radiosurgery (HFSRS) with intensity modulated radiotherapy (IMRT). Tere have been no other case reports of bilateral AVMs of this size success- fully treated with radiosurgery. In particular, the complete obliteration of the AVMs afer HFSRS with one year of treatment is noteworthy. 2. Case Report 2.1. History and Examination. A 12-year-old male presented to his primary care physician with a 3-month history of progressive gait abnormality. On physical examination, he had a subtle lef facial droop and hyperrefexia in the lef lower extremity. His gait was mildly ataxic with circumduction of the lef leg. He was unable to heel walk on the lef, and he had sidestepping with tandem gait. Toe walking was preserved. His motor and sensory exam was otherwise unremarkable. During his initial hospitalization for further evaluation, an MRI brain (Figure 1) showed evidence of bilateral basal ganglia and thalamic AVMs with evidence of hemorrhage and a small area of encephalomalacia adjacent to the AVM on the right. Te digital subtraction angiography (DSA) showed