To investigate the histological characteristics of oligodendroglioma (ODG), 65 cases of ODG were observed with light microscopy and partially with immunohistochemistry. According to WHO classification of tumors, 65 cases of ODG were graded in degree of differentiation of tumor cells. Of these, 19 cases belonged to grade I, 32 grade II, and 14 grade III.
Conclusion: Except the degree of differentiation, some other criterlons as cellular density, mitotic activities, and the presence of focally concentrated apoptotic cells are closely related to grading of ODG.