Stereotactic biopsies represent a routine
neurosurgical procedure for the diagnosis of intracranial
lymphomas and selected diffusely infiltrating
gliomas. Acquisition of tissue samples that do not allow correct
tumor typing and grading is, however, not uncommon. Five-
aminolevulinic acid (5-ALA) has been shown to accumulate in malignant
tumor tissue. The aim of this study was to prospectively investigate the clinical usability of 5-ALA for intraoperative detection of representative tissue in stereotactic
tumor biopsies. Fifty consecutive patients underwent frameless stereotactic biopsy for a suspected
brain tumor. 5-ALA was administered 4 h before
anesthesia. Serial biopsy samples were obtained and intraoperatively checked for 5-ALA fluorescence (strong, vague, or none) using a modified neurosurgical microscope. All samples were examined for the presence of representative
tumor tissue according to neuroimaging (MRI, positron emission tomography, and/or chemical shift imaging) and histopathological parameters. Visible 5-ALA fluorescence was observed in 43/50 patients (strong in 39 and vague fluorescence in four cases). At biopsy target, 52/53 samples of
glioblastomas, 9/10 samples of
gliomas grade III, and 14/16 samples of
lymphomas revealed strong 5-ALA fluorescence. Samples with strong 5-ALA fluorescence were only observed at, but not outside the biopsy target. All tissue samples with strong 5-ALA fluorescence were representative according to our neuroimaging and histopathological criteria (positive predictive value of 100%). Our data indicate that strong 5-ALA fluorescence is a reliable and immediately available intraoperative marker of representative
tumor tissue of
malignant gliomas and intracranial
lymphomas in stereotactic biopsies. Thereby, the application of 5-ALA in stereotactic
brain tumor biopsies may in future reduce costs for operating room and neuropathology and may decrease procedure-related morbidity.