Clinico-pathological correlations in meningiomas: a DNA and immunohistochemical study

We have studied 41 meningiomas classified histologically as benign, atypical or anaplastic. There were 26 females and 15 males and the mean age was 53 years. 36 tumours were supratentorial, 4 infratentorial and one spinal. Flow cytometry was performed on paraffin-embedded tissue using a selective staining technique for DNA. The ploidy index of DNA and percentage of cells in the S and G2/M phases were calculated. Results were correlated with clinical, histological and immunohistological data. 16/41 tumours were found to be diploid, 17/41 aneuploid and 8/41 could not be analysed. Significant correlations were found between aneuploid tumours and some qualitative features such as recurrence, pleomorphism, high cellular density, mitotic activity and brain and soft tissue infiltration. A high proliferative index appeared to be associated with clinical aggressiveness. No particular correlation between the expression of cytokeratin and epithelial membrane antigen markers and flow cytometry was found. Our results suggest that DNA flow cytometry in meningiomas may be of value in predicting the behaviour of these neoplasms and confirm that epithelial pattern in meningiomas is not linked to increased anaplasia or poor prognosis.