Multifocal recurrence of medulloblastoma: a long follow-up case study

Medulloblastoma is the most common malignant brain tumor in pediatric patients. Leptomeningeal dissemination often occurs in the spinal canal and rarely into the supratentorial as an extra-axial lesion. This study followed an 8-year progression of multifocal medulloblastoma recurrence as supratentorial metastasis that mimics an intra-axial mass of the temporal lobe. Pathologic examination of the temporal mass showed densely packed small round blue cells that are distributed in a ribboning pattern with areas of necrosis, rosette formation, and mitosis. Ki-67 immunohistochemical staining of the tumor showed a high proliferation index of 40% and revealed positive results for synaptophysin and negative results for glial fibrillary acidic protein and β-catenin. A long follow-up is essential to diagnose the recurrence and elucidate the progression of medulloblastoma.