Intracranial aneurysm formation after radiotherapy for medulloblastoma.

BACKGROUND: The development of an intracranial aneurysm after radiotherapy is rare but secondary effect of cranial irradiation in a primary disease treatment.

CASE DESCRIPTION: The patient was a 17-year-old male adolescent who was diagnosed as having a posterior fossa medulloblastoma when he was 8 years old. He had undergone tumor resection with radiotherapy and chemotherapy. A distal posterior inferior cerebellar artery aneurysm was identified by magnetic resonance imaging 8 years after radiotherapy and grew rapidly throughout the next 1 year. The patient underwent microsurgical clipping and was discharged without deficit.

CONCLUSION: This experience demonstrates that physicians caring for patients who have undergone intracranial radiotherapy should carefully consider the possibility of an aneurysmal formation when conducting follow-up imaging.