Immunohistochemical demonstration of glial fibrillary acidic protein (GFAP) in nasal gliomas.

Using the Sternberger method (Immunoluk Histoset KIT) GFAP (glial fibrillary acidic protein) was demonstrated immunohistochemically in 4 nasal gliomas. In these histologically complex tumour-like lesions mesenchymal, epithelial, and neuroglial tissues as well as small groups of scattered glial elements could be differentiated specifically by the highly sensitive GFAP immunoperoxidase technique. GFAP was present in astrocytes and astrocyte-like differentiations. The reactivity of cell processes was essentially lower. The GFAP immunostain does not always correlate with Mallory's phosphotungstic acid hematoxylin (PTAH) stain and Gallyas' silver impregnation method for astrocytes. Additionally the immunohistochemical investigation of semithin sections prepared by the so-called pop off technique after Bretschneider et al. (1981) allows the correct localization of GFAP in astrocytes and their modulations. Furthermore, in this study, the intimate connection of epithelium and glial cells as well as astrocytes containing hemosiderin granules could be demonstrated. The latter findings suggest a possible phagocytotic activity of astrocytes. Our results show that the demonstration of GFAP by the Sternberger method is a valuable aid in establishing astrocytic glial differentiations and modulations in complex tumour-like lesions such as nasal gliomas.