Congenital Glioblastoma with Distinct Clinical and Molecular Characteristics: Case Reports and a Literature Review

Background The molecular diagnosis of brain tumors is important in classifying tumors and determining appropriate treatment. Congenital glioblastoma multiforme (GBM) is a rare tumor that occurs in infants, and the prognosis is poor. Approximately 60 patients diagnosed with congenital GBM have been reported. However, few reports have conducted molecular analyses of congenital GBM. Case Description We describe 2 congenital GBM patients treated in our hospital, and report results of immunohistochemistry, fluorescent in situ hybridization (FISH), direct sequencing, and methylation analyses. Surgery was performed on both patients at 2 months old, and the cases were diagnosed as glioblastoma. Immunohistochemical staining, FISH, and direct sequencing were positive for glial fibrillary acidic protein and ATRX, partially positive for p53, showed no alteration of isocitrate dehydrogenase 1 R132H, H3F3A, HIST1H3B, and BRAF, and indicated no codeletion of 1p and 19q. Methylation analysis of 1 patient identified copy number aberrations of 4 genes: deletions of CDK6 and CDKN2A/B, and a fusion of MET. One patient received chemotherapy consisting of ranimustine, interferon-beta, carboplatin, and etoposide, whereas the other patient received chemotherapy with the modified Children's Cancer Group study-9921 protocol. Residual tumors in both patients were decreased, and they achieved 18-year- and 9-month progression-free survival, respectively. In addition, we reviewed 65 previously reported congenital GBM patients, and found they have better prognosis than pediatric and adult GBM, and long-term survival can be expected. Conclusions Congenital GBM demonstrates clinical and molecular characteristics that are different from those of pediatric or adult GBM.