Asymptomatic superficial siderosis after posterior fossa tumor resection: illustrative case

BACKGROUND: Superficial siderosis of the central nervous system is a rare syndrome notable for the presence of hemosiderin deposition due to chronic, repetitive hemorrhages into the subarachnoid space. OBSERVATIONS: The authors presented a case of superficial siderosis in a 14-year-old girl. It arose as a late postoperative complication after resection of a medulloblastoma. Despite the patient being asymptomatic, surveillance imaging demonstrated diffuse hemosiderin deposition within the cerebellar folia and cisternal segments of cranial nerves VII and VIII on gradient echo (GRE) sequences. Formal audiometric testing demonstrated bilateral loss of high-frequency tone recognition consistent with early sensorineural hearing loss. A pseudomeningocele due to multiple dural defects was identified as the likely cause, and definitive surgical repair was performed. Intraoperatively, the presence of blood-tinged cerebrospinal fluid confirmed a diagnosis of superficial siderosis. LESSONS: This case highlighted the potential need to routinely include GRE or susceptibility-weighted sequences in postoperative surveillance imaging after resection of pediatric posterior fossa tumors.