Quantitative evaluation of nucleolar features on cytologic material in brain tumor diagnosis

Nucleolar-related features were quantified in toluidin blue-stained smears from 36 brain tumors in order to improve our knowledge of the nucleolar frequency, size and margination. It was observed that low-grade astrocytic tumors had high percentages of nucleolated cells but the nucleoli were mostly single with maximum nucleolar diameter smaller than 2.00 microns. The percentages of marginated nucleoli were also low, ranging between 3.00% and 30.00% (only one case had a higher percentage). The high-grade tumors, i.e. anaplastic astrocytomas and glioblastomas, did not significantly differ from low-grade astrocytomas in their percentages of nucleolated nuclei, but they showed a higher number of nuclei having three or more nucleoli and the mean nucleolar diameter was in general bigger than 2.00 microns. Glioblastomas had marginated nucleoli much more frequently than anaplastic astrocytomas, the percentage in all but one case being higher than 30.00%. The percentage of marginated nucleoli was much higher in glioblastomas than in metastases, while the nucleoli were bigger in the latter group. A wide range of values for most of the nucleolar-associated parameters was observed in the remaining non-astrocytic brain tumors. Our results, showing differences in nuclear number, size and margination in different brain tumors, lead us to consider it worthwhile to investigate nucleolar-related features and their relationships using a quantitative approach.