Medulloblastoma and juvenile pilocytic astrocytoma presenting as synchronous primary brain tumors in a child

Multiple metastatic brain tumors and multifocal primary brain tumors of a single histological type have been published in the adult and pediatric literature. However, the simultaneous occurrence of multiple primary brain tumors with different cell types is rare. Even more rare is the pediatric presentation of multiple primary brain tumors with different cell types. The authors describe the case of an 8-year-old boy who presented with a 2-week history of progressive headache, nausea and vomiting, and imbalance. Brain MR imaging demonstrated a heterogeneously enhancing mixed solid/cystic mass of the left cerebellar hemisphere and a larger, midline, more homogeneously enhancing lesion of the superior vermis. Spinal MR imaging was unremarkable. The patient underwent a suboccipital craniotomy and subsequent gross-total resection of both mass lesions. Pathological examination revealed the left cerebellar and superior vermian lesions to be a juvenile pilocytic astrocytoma and a medulloblastoma, respectively. The patient did well in the immediate postoperative period, was discharged home, and underwent neurooncological follow-up. To the best of the authors' knowledge, they describe the first known pediatric case in which a medulloblastoma and a juvenile pilocytic astrocytoma presented as synchronous primary brain tumors. They review the literature on multiple primary brain tumors with different histological characteristics and rehash potential mechanisms for their development.