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.