Snap Shot A 5-year-old child presents with an occipital headache, an ataxic gait, nystagmus, and papilledema. Introduction A glial tumor The most common posterior fossa tumor in childhood Posterior fossa tumors are most common in children Presentation Posterior fossa tumors often present with ataxia and nystagmus Astrocytomas of the third ventricle present with symptoms of an elevated ICP such as headache, nausea, vomiting, hydrocephalus, and seizures Tumors of the cerebellar vermis cause truncal ataxia that is most obvious when the patient is sitting down Evaluation Imaging Surgical biopsy with histologic diagnosis Treatment Have the best posterior fossa tumor prognosis, with a 90% five year survival rate