Irreversible blindness from hydrocephalus in recurrent pediatric pilocytic astrocytoma: a case report.

Background: Pilocytic astrocytoma (PA) is the most common pediatric brain tumor, typically associated with favorable outcomes following surgical resection. However, irreversible vision loss due to elevated intracranial pressure (ICP) in posterior fossa PA is rare and often underrecognized. This case highlights the consequences of delayed detection of tumor recurrence and the critical importance of long-term surveillance in pediatric brain tumor survivors. Case Presentation: A 14-year-old male with a history of posterior fossa PA resection at age 4 presented with progressive headache, vomiting, and rapidly deteriorating vision after being lost to follow-up for 10 years. Neuroimaging revealed tumor recurrence with obstructive hydrocephalus. Imaging confirmed that the recurrent tumor was confined to the posterior fossa with no extension to or compression of the optic nerves, chiasm, or tracts. Despite emergency cerebrospinal fluid diversion and subtotal tumor resection followed by CyberKnife radiotherapy (45 Gy in 25 fractions), the patient developed permanent bilateral blindness. Fundoscopy confirmed severe bilateral optic disc atrophy most likely secondary to prolonged elevated ICP rather than direct tumor compression, although alternative contributing mechanisms could not be entirely excluded given the complex clinical course. At six-month follow-up, the patient remained clinically stable with no tumor progression but persistent vision loss and residual cerebellar dysfunction. Conclusion: This case demonstrates that posterior fossa PA recurrence can lead to irreversible blindness, most likely through sustained elevated ICP, even in the absence of direct optic pathway involvement. It underscores the necessity of systematic long-term surveillance protocols and prompt hydrocephalus management in pediatric brain tumor patients to prevent devastating but potentially avoidable complications.