Delayed Recurrence of Hydrocephalus After Cauda Equina Schwannoma Resection Despite Normalization of CSF Protein: A Case Report

Abstract Hydrocephalus associated with spinal schwannoma is rare and often improves after tumor resection alone. However, cerebrospinal fluid (CSF) diversion may subsequently be required in some patients. A 79-year-old woman presented with progressive cognitive decline, repeated falls, and severe gait disturbance. Brain magnetic resonance imaging demonstrated ventriculomegaly with features suggestive of normal pressure hydrocephalus (NPH). Lumbar imaging performed before planned lumboperitoneal shunting revealed a large intradural extramedullary tumor at the L2–3 level. The tumor and its originating cauda equina root were completely removed. The intraoperative CSF protein concentration was markedly elevated at 474.4 mg/dL. After surgery, ventricular size decreased, CSF protein markedly declined, and cognition and gait improved. Bilateral subdural enlargement and a subsequent chronic subdural hematoma suggested that transient perioperative CSF loss may also have contributed to the early radiological improvement. Nevertheless, ventriculomegaly and neurological deterioration subsequently recurred despite normalization of the CSF protein concentration. Ventriculoperitoneal shunting performed 6 months after tumor resection resulted in further improvement in cognition and gait. Although a causal relationship between the schwannoma and hydrocephalus cannot be established and coexisting idiopathic NPH cannot be excluded, this case illustrates the potentially multifactorial course of hydrocephalus associated with a spinal intradural tumor. Early postoperative improvement does not guarantee durable recovery of CSF circulation, and longitudinal clinical and radiological follow-up is important.