Malignancy in vestibular schwannoma after stereotactic radiotherapy: a case report and review of the literature.

OBJECTIVES/HYPOTHESIS A relation between conventional radiotherapy and the development of intracranial neoplasma is well known, but radiation-associated tumor following stereotactic radiotherapy of vestibular schwannoma is underestimated. In this article we will study this relation by doing a complete literature review on all the malignant intracranial tumors that appeared following radiosurgery and adding a case of malignant vestibular schwannoma following stereotactic radiotherapy in a Neurofibromatosis type 2 patient. METHODS Literature review and discussion. RESULTS We found 26 cases of malignant brain tumor following stereotactic radiotherapy including our case. In 13 cases the tumor occurred in context of Neurofibromatosis type 2. None of the patients had a tumor size less than 2.5 cm. and the mean latency period between the radiotherapy and malignant tumor development was 5.8 years. CONCLUSION Patients with vestibular schwannoma should be made aware of the low incidence of the radiation-induced malignant changes and long-term follow-up is mandatory.