Correlation between argyrophilic nucleolar organizer region staining and brain tumor classification and grading.

Distinctions between benign and malignant tumors are less evident in the central nervous system than in other tissues. Since the level of cell proliferation is an important feature in tumor grading, we applied AgNOR in 50 cases of brain tumors with different grades and histological origins in order to check its efficiency in discriminating between benign and malignant cases. We found significant differences between the means of grade I (1.76) and grade IV (2.46) tumors. No significant differences were observed considering the same grading with distinct histological types or age of patients, reinforcing the efficiency of AgNOR.