Radiation-Induced Meningioma following Prophylactic Radiotherapy for Acute Lymphoblastic Leukemia in Childhood

Background: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Although it was considered to be a poor prognostic disease, modern treatment protocols (aggressive chemotherapy and prophylactic cranial irradiation) have resulted in dramatically improved survival rates. In a group of low-risk ALL patients, the 5-year survival rate is estimated to be 85%. However, ALL patients who undergo this treatment are at risk of developing secondary neoplasms related to treatment, which has become an increasingly recognized problem. Case Description: A 3-year-old boy with ALL was successfully treated with chemotherapy (vincristine, prednisolone, mercaptopurine and methotrexate) and prophylactic cranial irradiation (total 18 Gy). At the age of 23, he was admitted to our hospital for weakness in the right leg. Computed tomography and magnetic resonance imaging revealed a parasagittal tumor of the left frontoparietal lobe with perifocal edema. The tumor was completely removed surgically and pathohistologically diagnosed as atypical meningioma. Conclusion: Long-term survivors who received radiotherapy for ALL in childhood are at risk for late complications, including radiation-induced meningioma. Therefore, careful follow-up neurological examinations, for example magnetic resonance imaging, are indicated in these patients. In addition, late complications should be taken into account during the initial planning of prophylactic radiotheraphy dosage, which has implications for informed consent of the patient.