The authors describe a case of glioblastoma multiforme (GBM) associated wit
h previous gamma knife radiosurgery for a cerebral arteriovenous malformati
on (AVM). A 14-year-old boy had undergone radiosurgery for an AVM, which wa
s performed using a 201-source Co-60 gamma knife system at another institut
ion. The maximum and margin radiation doses used in the procedure were 40 a
nd 20 Gy, respectively. One year after radiosurgery, the patient noticed on
set of mild left hemiparesis due to radiation necrosis.
Six and one-half years after radiosurgery, at the age of 20 years, the pati
ent experienced an attack of generalized tonic-clonic seizure. Magnetic res
onance (MR) imaging revealed the existence of a brain tumor in the right pa
rietal lobe. The patient underwent an operation and the histological diagno
sis of the lesion was GBM. Ten months following the operation, that is, 99
months postradiosurgery, this patient died.
To the best of the authors' knowledge, this is the first reported case of a
neoplasm induced by radiosurgery for an AVM and the second case in which i
t occurred following radiosurgery for intracranial disease.