Treatment-related calvarial lesions in pediatric brain tumor survivors

Background: Despite improved survival, many pediatric brain tumor survivors receiving radiation therapy (RT) experience late effects. Procedure: To study calvarial lesions in this population, we retrospectively reviewed records of patients undergoing neurosurgical evaluation for calvarial bone lesions detected in posttreatment follow-up imaging at St. Jude Children's Research Hospital. Primary tumor diagnosis, treatment, imaging, surgical intervention, and histopathology from patients with radiographic evidence of lesions followed for ≥2 years post-RT were studied. Results: For 17 patients with 18 index lesions, median time to lesion manifestation was 2.34 years. Medulloblastoma patients developed lesions at a shorter interval from RT than ependymoma patients (P =.05). Twelve of 14 lesions requiring surgery were benign fibro-osseous or sclerotic. Two malignant lesions distinct from the primary tumor had genetic predisposition to malignancy. Conclusion: Most calvarial lesions arising post-RT are benign and fibro-osseous. Serial imaging is recommended, and high index of suspicion for malignant lesions is warranted for patients genetically predisposed to cancer.