Immunohistochemical diagnosis of nervous system neoplasms.

Classic histopathologic study revealed a series of highly treasured criteria for diagnosing central and peripheral nervous system neoplasms. The advent of immunohistochemistry galvanized further improvements in the accuracy of diagnostic neurooncologic pathology, and moreover, enriched our understanding of tumor histogenesis. Now with the tremendous technical advances in immunodetection and the commercial availability of high-quality monoclonal and polyclonal antibodies, the potential for first-rate diagnostic assessment is available to practically every laboratory, regardless of how small or remotely located. Intensive immunohistochemical analysis of nervous system neoplasms has taught us that neuroectodermal cells have a limited repertoire of highly redundant antigenic phenotypes and that neoplastic cells usually mimic their non-neoplastic immature or fully differentiated counterparts. These observations led to the concept that a panel of antibodies ought to be used to identify the "immuno-gestalt" of tumors, because it is often difficult if not impossible to subcategorize the tumors on the basis of a single immunohistochemical determination. The ensuing tour through the immunodiagnostic neurooncology summarizes approximately 10 years of original work in this field. I have attempted to provide consensus opinions, and whereever appropriate, highlight dissenting arguments. The salient immunohistochemical features of most nervous system tumors also are summarized in tabular form to facilitate diagnostic considerations at your own institutions.