Typical symptoms of normal-pressure hydrocephalus caused by choroid plexus papilloma in the cerebellopontine angle: a case report

Abstract Background Choroid plexus papillomas (CPPs) are rare benign intracranial tumors. Here, we report a rare case of CPP presenting with typical symptoms of normal-pressure hydrocephalus not with obstructive hydrocephalus. Case description A 45-year-old female presented with a 6-year history of headache and typical symptoms of normal-pressure hydrocephalus (NPH) such as gait disturbance, urinary incontinence, and cognitive dysfunction in addition to the more common symptoms of choroid plexus papillomas (CPP), such as lower cranial nerve dysfunctions and ataxia. CPP arose from the right lateral recess of the fourth ventricle and extended to the cerebellopontine angle. Magnetic resonance images did not show any radiographic evidences of obstruction of aqueduct, foramen of Magendie, or foramen of Luschka on the contralateral side. We speculated that hydrocephalus was associated with the cerebrospinal fluid (CSF) overproduction by a CPP originating from the choroid plexus of the lateral recess and extending laterally into the cerebellomedullary fissure (CMF). Surgical excision was performed with the trans-CMF approach. Her symptoms of NPH had disappeared. In addition to improved clinical symptoms, radiographic findings showed mitigation of ventricular dilatation. Conclusions We conclude that the hydrocephalus was of a communicating type and caused by CSF overproduction. The lateral route of the trans-CMF approach is useful for the dissection of tumors that extend into the unilateral cerebellomedullary cistern through CMF. This approach not only enables sufficient exposure for resection but also avoids damage to the surrounding structures.