Neuroendoscopic fenestration of expanding cavum septi pellucidi: A case report

Abstract

The authors report a rare case of expanding cavum septi pellucidi (CSP) occuring in a 65-year-old man secondary to obstructive hydrocephalus, bacterial meningitis and ventriculo-peritoneal shunt procedure. Preoperative perfusion MRI demonstrated hypoperfusion of the corpus callosum, and we subsequently performed endoscopic transventricular fenestration of the cystic CSP. Intraoperative neuroendoscopic observation using rigid endoscope revealed that the medial wall of the lateral ventricle protected and was pulsing, but the foramen of Monro was not obstructed. The expanding CSP wall was fenestrated and biopsied and communicated within the ventricular systems using a 4mm-steerable fiberscope, and confirmed the abscence of abnormal structures within CSP cavity. Postoperatively, the CSP was collapsed to a normal size and improvement of the regional blood flow of the corpus callosum was confirmed. Histological study of CSP wall revealed massive gliosis with perivascular accumulation of inflammatory cells. We consider that this was an aquired cyst of the CSP, which expanded due to cheek valve mechanism between the lateral ventricle and the wall of CSP, and emphasize the efficacy of neuroendoscopic strategy for symptomatic CSP.