Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) has been broadly recognized as a beneficial tool for the resection of glioblastoma multiforme (GBM). Fluorescence in the ventricular walls, which were apparently free of macroscopic tumor or MR imaging enhancement indicative of CSF dissemination, was detected during surgery for GBM. To evaluate the clinical significance of the 5-ALA fluorescence, the authors resected ventricle wall tissue together with the adjacent tumors for pathological examination and then followed up the clinical courses of the patients.
Seven consecutive GBMs located near the lateral ventricle were surgically treated using a fluorescence-guided technique with 5-ALA at the authors' hospital since acquiring instrumentation for the detection of 5-ALA fluorescence in 2007. All of the procedures were performed using a ventricular entry, and 5-ALA fluorescence of the ventricular wall was detected despite the absence of macroscopic tumor invasion of the wall.
A pathological examination of the resected ventricular wall tissues revealed tumor cells in 6 of the 7 cases and disruption of the ependymal cell layer in all 7 cases. Delayed communicating hydrocephalus followed surgery in all 7 patients, and ventricular wall enhancements on MR imaging were demonstrated after hydrocephalus in 2 of the patients.
Data in this study suggest that 5-ALA fluorescence of the ventricular wall may be predictive of postoperative hydrocephalus associated with CSF dissemination even in cases without evidence of CSF dissemination on MR imaging studies before surgery. The authors also speculate that postoperative radiotherapy covering the whole ventricular system may be a better therapeutic option for these patients.