2000; Skjoth-Rasmussen et al. 2010). Deeper locations like the thalamus, basal ganglia, or brain stem and larger volumes of therapy carry greater risks of deficits (www.selleckchem.com/products/BIBF1120.html Miyawaki et al. 1999; Flickinger et al. 2000). Most studies have documented an ~2–3% risk of radiation necrosis with permanent neurologic deficits (Fabrikant et al. 1992; Pollock and Meyer 2004). Therefore, in an eloquent location such as the brain stem, even radiosurgery carries significant risks. Another disadvantage of radiosurgery Inhibitors,research,lifescience,medical compared to surgical resection is that patients continue to have hemorrhage risk until the AVM is completely obliterated.

Karlsson et al. reported the latency interval from radiosurgery to obliteration Inhibitors,research,lifescience,medical as lasting between 1 and 4 years. There is conflicting evidence regarding the risk of hemorrhage during the latency period. Steinberg et al. in 1990 and Fabrikant et al.

in 1992 reported an increased risk during this time. However, from a cohort of 500 patients, Schauble et al. presented strong evidence supporting a reduced risk of hemorrhage during the latency period (Maruyama et al. 2005). Improved seizure control may be an added benefit of radiation (Schauble et al. 2004). Approximately 10% of AVMs are located in the posterior cranial fossa and the prognosis Inhibitors,research,lifescience,medical is poor for patients with AVMs in this area (Drake et al. 1986). In 1986, Drake et al. reported a series of 66 surgically treated AVMs including ponto-medullary AVMs. Seven of these eight AVMs were <2.5 cm in diameter and one was ~5 cm in diameter. Of these eight, one patient died after exploration, and two patients had poor outcomes (Drake et al. 1986). Microsurgical resection Inhibitors,research,lifescience,medical of these deep AVMs leads to greater mortality and decreased rates of complete resection (Drake et al. 1986; Massager et al. 2000). Embolization has

not been used as the sole treatment of brain stem AVMs although there is no long-term analysis or randomized clinical trials (Duma et al. 1993; Kurita et al. 2000; Massager Inhibitors,research,lifescience,medical et al. 2000), previous studies document that the most efficacious and safest mode of treatment for brain stem AVMs is modified stereotactic radiosurgery (Flickinger 1989; ADP ribosylation factor Lunsford et al. 1991; Flickinger et al. 1992, 2000, 2002; Duma et al. 1993; Pollock et al. 1996, 1998; Karlsson et al. 1997; Kurita et al. 2000; Massager et al. 2000; Bhatnagar et al. 2001; Hadjipanayis et al. 2001; Pollock and Flickinger 2002). The Flickinger study and the larger Karlsson study mentioned earlier, did not report any numbers for the gamma knife outcome on the brain stem AVMs. This case report follows the course of a patient with a large brain stem AVM that was completely eradicated with gamma knife therapy. Case Report A 37-year-old right-handed white female presented in 1997 with a 2-year history of progressive left hemiparesis, ataxia, facial pain, and tongue numbness.