ORIGINAL ARTICLE Strong 5-aminolevulinic acid-induced fluorescence is a novel intraoperative marker for representative tissue samples in stereotactic brain tumor biopsies Georg Widhalm & Georgi Minchev & Adelheid Woehrer & Matthias Preusser & Barbara Kiesel & Julia Furtner & Aygül Mert & Antonio Di Ieva & Boguslaw Tomanek & Daniela Prayer & Christine Marosi & Johannes A. Hainfellner & Engelbert Knosp & Stefan Wolfsberger Received: 29 June 2011 / Revised: 20 September 2011 / Accepted: 8 October 2011 / Published online: 10 March 2012 # Springer-Verlag 2012 Abstract Stereotactic biopsies represent a routine neurosur- gical 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 biop- sies. Fifty consecutive patients underwent frameless stereo- tactic 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 fluo- rescence (strong, vague, or none) using a modified neuro- surgical microscope. All samples were examined for the presence of representative tumor tissue according to neuro- imaging (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 glio- mas 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 histo- pathological 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 lympho- mas 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. G. Widhalm : G. Minchev : B. Kiesel : A. Mert : A. Di Ieva : E. Knosp : S. Wolfsberger Department of Neurosurgery, Medical University Vienna, Vienna, Austria G. Widhalm : A. Woehrer : J. A. Hainfellner Institute of Neurology, Medical University Vienna, Vienna, Austria M. Preusser : C. Marosi Department of Internal Medicine I, Medical University Vienna, Vienna, Austria J. Furtner : D. Prayer Department of Radiology, Medical University Vienna, Vienna, Austria A. Di Ieva Center for Anatomy and Cell Biology, Medical University Vienna, Vienna, Austria G. Widhalm : G. Minchev : A. Woehrer : M. Preusser : B. Kiesel : J. Furtner : D. Prayer : C. Marosi : J. A. Hainfellner : E. Knosp : S. Wolfsberger (*) Comprehensive Cancer Center—Central Nervous System Tumours Unit (CCC-CNS), Medical University Vienna, Waehringer Guertel 18-20, 1097 Vienna, Austria e-mail: stefan.wolfsberger@meduniwien.ac.at B. Tomanek Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada Neurosurg Rev (2012) 35:381–391 DOI 10.1007/s10143-012-0374-5