Application of silver colloidal staining method in the diagnosis of intracranial glioma

A silver colloidal staining technique for the demonstration of argyrophilic nucleolar organizer regions (Ag-NORs) was used on the paraffin sections of reactive gliosis and grade I astrocytoma tissue. Quantitative as well as qualitative differences of Ag-NORs were found between the cells of reactive gliosis and grade I astrocytoma. In cases of reactive gliosis, the Ag-NOR counts averaged 1.19 +/- 0.16 per nucleus, while in grade I astrocytoma, Ag-NOR counts averaged 2.36 +/- 0.32 per nucleus (P < 0.05). Compound Ag-NORs were also seen in the nuclei of cells in grade I astrocytoma while they were not present in the nuclei of cells in cases of reactive gliosis. The results of the study indicate that Ag-NOR technique is an useful method and can be applied in situations where a distinction between grade I astrocytoma and reactive gliosis becomes difficult at the light microscopic level.