2023 Volume 51 Issue 3 Pages 227-232
Recently, delayed development of intracranial aneurysms in the irradiation field has been reported as a complication of gamma knife radiosurgery (GKRS). We present a case of a ruptured anterior inferior cerebellar (AICA) aneurysm in the irradiation field, 28 years after GKRS for a right vestibular schwannoma (VS). A 66-year-old man underwent GKRS for a right VS. Twenty-eight years later, he experienced a sudden headache and vomiting, and brain computed tomography revealed a subarachnoid hemorrhage. Using digital subtraction angiography, a ruptured fusiform aneurysm was discovered in the meatal loop of the right AICA. Magnetic resonance imaging revealed a residual schwannoma and an aneurysm surrounded by the tumor in the right internal auditory canal (IAC). The patient underwent surgery 2 weeks after the onset. After removing the posterior wall of the IAC, the aneurysm was resected in one piece with the residual tumor. Although the patient experienced transient facial paralysis, he did not develop a brainstem or cerebellar infarction. He had a modified Rankin Scale score of 1 on discharge. Development of a cerebral aneurysm in the irradiation field is a rare delayed complication of GKRS. We achieved a good outcome with direct surgery for the GKRS-induced ruptured distal AICA aneurysm.
