Low-grade bone lesions in survivors of childhood medulloblastoma/primitive neuroectodermal tumor

Abstract

Objectives and rationale: 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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.