Low-grade Bone Lesions in Survivors of Childhood Medulloblastoma/Primitive Neuroectodermal Tumor

Abstract

Medulloblastoma/primitive neuroectodermal tumor (MB/PNET) is the most common malignant tumor of the central nervous system (CNS) in children. MB/PNET survivors are at an increased risk for developing second malignancies. Little has been reported on development of low-grade lesions of the calvarium in the radiation field in MB/PNET survivors. The purpose of this study was to assess the frequency of the low-grade bone lesion development in the radiotherapy field in pediatric MB/PNET survivors and describe the imaging characteristics of these lesions. Institutional review board approval was obtained for this retrospective review which was compliant with Health Insurance Portability and Accountability Act. Forty-one MB/PNET patients (29 male) who survived for at least 2 years after initiation of radiation therapy were included. The medical records were reviewed. The most recent available brain magnetic resonance imaging studies were evaluated. Three patients (7.3%) developed low-grade calvarial lesions and underwent resection and/or biopsy of the lesions. There were one Langerhans cell histiocytosis, one benign spindle cell lesion with myxoid change, and one fibrous dysplasia. Development of low-grade bone lesions of calvarium is not very rare in pediatric PNET/MB survivors. Bones in the radiation therapy field need to be carefully examined for assessment of secondary lesions.