title: Intraoperative fluorescein staining for benign brain tumors.
abstract: OBJECTIVE
  Successful use of high-dose fluorescein-sodium (20mg/kg) with a standard light microscope for resection of high-grade gliomas, meningiomas, hemangioblastoma and metastases was reported. The principle of brain tumor staining by fluorescein-sodium (Fl-Na) consists in the accumulation of fluorescein in brain tumors with impaired blood-brain barrier. The aim of our study was to investigate for the first time the usefulness of high-dose fluorescein in patients operated on for benign neuroepithelial brain tumors (grade I WHO tumors) with contrast enhancement on magnetic resonance imaging.
  
  
  METHODS
  Our study included 11 patients operated on for benign neuroepithelial primary brain tumors with contrast enhancement on magnetic resonance imaging (MRI): pilocytic astrocytomas (5 patients), dysembrioplastic neuroepithelial tumors (4) and gangliogliomas grade I (2). In all cases, Fl-Na was injected intravenously (20mg/kg) just after the craniotomy using a peripheral venous line. The dural opening was performed 10min later. Microsurgical tumor resection using conventional neurosurgical microscope guided by the fluorescein staining was performed.
  
  
  RESULTS
  Complete resection of the yellow-green stained tissue was achieved in 10 patients confirmed by postoperative control MRI study. Subtotal resection of the colored tissue was achieved in one case with fourth ventricle pilocytic astrocytoma because of the involvement of the medial eminence and functional constraints discovered during intraoperative neuromonitoring. Three patients have had a postoperative volume of resection greater than the tumor volume because of the planed perilesionectomy by our epilepsy surgery team. Surrounding tissue not stained by Fl-Na was obtained in these 3 cases. The histopathological examination did not find tumor tissue in the perilesional Fl-Na negative tissue. On the other hand, all 11 Fl-Na positive specimens presented signs of tumor involvement. We did not observe complications related to the use of high dose Fl-Na.
  
  
  CONCLUSIONS
  High doses intravenous Fl-Na seems to be a useful intraoperative technique for delineation of benign neuroepithelial brain tumors with contrast enhancement. Further larger studies may reveal the real value of high doses Fl-Na as intraoperative method for increasing the extent of resection in these particular indications.
authors.affiliation: Department of Neurosurgery, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria; Medical University, Sofia, Bulgaria. Electronic address: minkin@abv.bg.
authors.forename: Krasimir
authors.initials: K
authors.lastname: Minkin
authors.affiliation: Department of Neurosurgery, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Emanuil
authors.initials: E
authors.lastname: Naydenov
authors.affiliation: Department of Neurosurgery, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Kaloyan
authors.initials: K
authors.lastname: Gabrovski
authors.affiliation: Department of Neurosurgery, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Petia
authors.initials: P
authors.lastname: Dimova
authors.affiliation: Department of Neuroradiology, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Marin
authors.initials: M
authors.lastname: Penkov
authors.affiliation: Department of Neurosurgery, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Rositsa
authors.initials: R
authors.lastname: Tanova
authors.affiliation: Department of Neuropathology, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Sevdelin
authors.initials: S
authors.lastname: Nachev
authors.affiliation: Department of Neurosurgery, University Hospital "Saint Ivan Rilski", Sofia, Bulgaria.
authors.forename: Kiril
authors.initials: K
authors.lastname: Romanski
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D019793:Fluorescein; D006801:Humans; D008297:Male; D018302:Neoplasms, Neuroepithelial / Q000000981:diagnostic imaging* / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019793:Fluorescein
keywords: 5-ALA; DNET; Epilepsy surgery; Fluorescein; Ganglioglioma; Pilocytic astrocytoma