Quantitative evaluation of recurrent meningiomas.

Clinical, histological and karyometric parameters, nuclear DNA content and the number of nucleolar organizer regions were investigated in 9 recurrent meningiomas and 10 meningiomas which had not recurred within a 10-year period. There were no significant differences between the two groups as to age, sex, site of the tumours and most of the histological parameters scored. Recurrent tumours showed a higher number of mitotic figures and the nucleolus was visible in most of the cells. Cell density, nuclear area, perimeter and nuclear DNA content had values with no statistically significant differences between the two groups. However, significant differences were found in the distribution of the nuclei in the different ploidy regions. Most of the nuclei in the non recurrent cases were in the diploid range, whereas in recurrent tumours there was a reduction in the number of diploid cells associated with an increase in 2c--4c and 4c components. Recurrent tumours also showed a higher number of nucleolar organizer regions positively stained using an argyrophil method. The mitotic count and the nucleolar organizer regions appeared to be the best predictors for recurrence.