title: Radiation-induced cerebellar glioblastoma at the site of a treated medulloblastoma: case report.
abstract: Radiation-induced glioblastoma multiforme (GBM) is a rare complication of radiotherapy. The authors report such a case occurring 10 years after treatment of cerebellar medulloblastoma. The patient was a 15-year-old boy who had undergone a gross-total removal of a medulloblastoma and received radiation therapy at the age of 5 years. He had experienced no tumor recurrences for 10 years until a new enhancing mass was found at the original site of the medulloblastoma. Following its resection the new lesion was found to be a GBM and there was no evidence of a medulloblastoma. The second tumor developed at the same site as the previous one after a sufficient latent period and fulfilled the criteria for a radiation-induced neoplasm. The original tumor cells expressed synaptophysin without p53 overexpression, a characteristic feature of medulloblastomas. In contrast, cells from the later tumor expressed glial fibrillary acidic protein and p53 but not synaptophysin. A sequence analysis of the p53 gene showed deletion at codon 233 and a C to G transition at codon 278 in the GBM but no mutation in the medulloblastoma. A GBM specimen revealed no amplification of the epidermal growth factor receptor compared with a normal control specimen. In conclusion, the clinical features of a radiation-induced GBM are similar to that of the primary GBM, whereas its genetic alterations render it a secondary GBM. These findings indicate that radiation-induced GBM should be considered a distinct clinical entity.
authors.affiliation: Departments of Pathology and Therapeutic Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Seung-Yeob
authors.initials: SY
authors.lastname: Yang
authors.forename: Kyu-Chang
authors.initials: KC
authors.lastname: Wang
authors.forename: Byung-Kyu
authors.initials: BK
authors.lastname: Cho
authors.forename: Young-Yim
authors.initials: YY
authors.lastname: Kim
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Lim
authors.forename: Sung-Hye
authors.initials: SH
authors.lastname: Park
authors.forename: Il Han
authors.initials: IH
authors.lastname: Kim
authors.forename: Seung-Ki
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D002528:Cerebellar Neoplasms / Q000209:etiology* / Q000235:genetics / Q000532:radiotherapy / Q000628:therapy*; D016158:Genes, p53 / Q000235:genetics; D005909:Glioblastoma / Q000209:etiology* / Q000235:genetics; D006801:Humans; D008297:Male; D008527:Medulloblastoma / Q000235:genetics / Q000532:radiotherapy / Q000628:therapy*; D009381:Neoplasms, Radiation-Induced / Q000235:genetics; D016609:Neoplasms, Second Primary / Q000235:genetics; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects*