The application of direct immunofluorescence to intraoperative neurosurgical diagnosis

A diagnostic problem can occur at the time of intraoperative consultation o f neurosurgical tumors as to whether the tumor is of neuroectodermal origin or whether it represents an epithelial metastasis from another site. Intra operative diagnoses based on hematoxylin and eosin stained frozen sections are often later confirmed by immunocytochemical analysis of formalin-fixed, paraffin-embedded tissue sections that are not available at the time of su rgery. The objective of the current study was to demonstrate that the appli cation of direct immunofluorescence to the intraoperative diagnosis of neur osurgical tumors would provide unequivocal, and nearly immediate results. T his report describes a new application of an existing technique for an opti mized, rapid procedure utilizing direct immunocytochemistry with fluorescen ce-labeled primary antibodies to analyze surgical biopsies intraoperatively . The examination of five neurosurgical biopsies established a neuroectoder mal origin of three tumors via immunolabeling for glial fibrillary acidic p rotein (GFAP) and lack of labeling with keratin markers, whereas several me tastatic lung carcinomas were identified by immunostaining for keratin, but not GFAP, markers. The results of the direct immunolabeling method were un equivocal and required only minutes. The same diagnoses were confirmed by s tandard immunocytochemical labeling of formalin-fixed, paraffin-embedded se ctions, though it required several days to obtain the results. Direct immun ofluorescence using fluorescently conjugated primary antibodies is a practi cal and rapid method for deciding whether a neurosurgical tumor is a primar y glial or an epithelial metastatic tumor in origin. It is the first report ed application of the technique for this aspect of rapid neurosurgical diag nosis. (C) 2000 Elsevier Science B.V. All rights reserved.