Huge Cyst Formation after Gamma Knife Radiosurgery for Arteriovenous Malformation: A Case Report

ABSTRACT

Radiosurgery is effective in obliterating cerebral arteriovenous malformation(AVM), and delayed cyst formation after radiosurgery is very rare. An 18-year-old man underwent Gamma Knife radiosurgery for arteriovenous malformation located in the left frontotemporal area, which had manifested with hemorrhaging. The 15,01cm3 nidus was covered with a 50% isodose volume. A central dose of 50Gy was used to obtain a marginal dose of 25Gy. One year later, he developed headache and right hemiparesis. MRI showed a huge, multilobulated cyst around the AVM. Follow-up cerebral angiography showed partial obliteration of the AVM nidus. Removal of cystic fluid(about 70cc) was done by stereotactic method, which was revealed as translucent, xanthochromic but had no tumor cell. Two months later, reaccumulation of the cyst was seen on the follow-up MRI insertion setting of Ommaya reservoir was performed. For the diagnosis of complications after radiosurgery for AVM, follow-up study, will be needed.