This case illustrates the potential growth rate of an atypical meningioma in a pediatric patient, emphasizes one of the potential risks after therapeutic radiation, and underscores the importance of clinical evaluation and follow up of the symptomatic patient after tumor resection and radiation therapy. The authors report a case of a radiation-induced atypical meningioma of the olfactory groove in a 13-year-old girl who received 36 Gy of radiation to the craniospinal axis and 72 Gy to the primary site of a primitive neuroectodermal epithelial tumor of the left parietooccipital lobe when she was 4 years of age. This tumor was not present on routine magnetic resonance imaging performed 13 months prior to the discovery of this lesion or on computerized tomography scanning obtained 6 months prior to the discovery of this tumor. At the time of its discovery, the tumor was 5 x 5 x 4 cm. This tumor was resected and the patient's symptoms improved. This case illustrates the importance of continued close follow up after cranial irradiation in the pediatric population.