Surgical treatment for choroid plexus tumors in the fourth ventricle: brain stem infiltration hinders total extirpation.

The significance of surgery for choroid plexus tumors is well established, but surgical resection of those in the fourth ventricle has not been evaluated. This study reviewed five consecutive patients with choroid plexus tumors in the fourth ventricle treated in our institute between 1996 and 2005, focusing on the factors that hindered total extirpation. Two cases were choroid plexus papillomas, and three cases were choroid plexus carcinomas. Preoperative T2-weighted magnetic resonance imaging showed a diffuse high-intensity lesion in the brain stem in four patients. Infiltration into the fourth ventricle floor was apparent in all five patients during surgery, which hindered total resection of the tumors without neurological deterioration. Intraoperative bleeding was well controlled in all five patients by cauterizing the feeding arteries at the early stage of surgery through the telovelar approach. Performance status was improved in all patients postoperatively. All patients with choroid plexus carcinomas underwent radiation therapy after the surgical removal. No patient suffered tumor progression within the follow-up of 24-129 months (mean 64 months). Total resection of choroid plexus tumors in the fourth ventricle is difficult because of invasion into the fourth ventricle floor. Adjuvant therapy for choroid plexus tumors with brain stem infiltration must be established.