Nicholas J. Pytel, DO; Diane Puccetti, MD
Research Proposal: Medulloblastoma is a malignant tumor diagnosed in 12-25% of pediatric brain tumors, 77% before the age of 19. In adulthood, the rate sharply declines with increasing age to be only diagnosed in 0.4-1% of adult brain tumors. These tumors are diagnosed typically after symptoms are noted consistent with increased intracranial pressure. We present a case of a young adult who was followed with serial MRI scans due to history of headaches and over time developed a lesion in the cerebellum that was later diagnosed as a medulloblastoma. We present this case as a natural history of medulloblastoma and will include a review of the literature. Patient AG had the original MRI brain scan for chronic headaches yielding only a right posterior fossa arachnoid cyst. Four years later, persistent headaches warranted another scan showing a new lesion with T2 FLAIR hyperintensity in the left cerebellar hemisphere. Serial scans over two years showed progression in size and complexity of this new lesion originally thought benign. AG underwent craniotomy with mass resection that resulted in cytoplasmic beta-catenin positive medulloblastoma without anaplasia on neuropathology. It was also without metastasis or CSF involvement. Post-operative imaging showed a small suspicious area near the resection cavity which biopsies later proved positive for residual medulloblastoma greater than 1.5 cm, thus placing this patient into the high-risk treatment category. AG elected proton therapy (36 in the craniospinal region with posterior fossa boost) with vincristine following protocol ACNS0331 with maintenance therapy afterward. AG has since been followed with serial MRI scans without evidence of residual disease. After reviewing the literature, low occurrences of incidental CNS tumors have been found in trauma and research cases. It is rare to have radiographic evidence of the onset of a malignant brain tumor. We present our case and literature review of this entity.