Characterization of nuclear DNA content, proliferation index, and nuclear size in a series of 181 meningiomas, including benign primary, recurrent, and malignant tumors.

The characterization of nuclear area, the proliferation index, and nuclear DNA content was carried out by means of digital cell image analysis, which makes it possible to compute morphometric and densitometric features on Feulgen-stained nuclei from archival, that is, formalin-fixed, paraffin-embedded materials. The 181 meningiomas studied included 173 classic (41 meningotheliomatous, 27 fibroblastic, 82 transitional, nine psammomatous, eight angiomatous and six hemangioblastic tumors) and eight malignant meningiomas (three hemangiopericytomas and five tumors that we labeled HFM, that is, tumors exhibiting evidence of histological features of malignancy). The results reveal a strong relationship between incomplete surgical resection and recurrence on the one hand and between the probability of recurrence and histopathological type on the other. Whereas neither nuclear area nor nuclear DNA content assessments were helpful in distinguishing the six classic and the two malignant meningioma subgroups, a statistically significant increase in proliferative activity was observed in the malignant meningiomas as compared with classic ones, excepting hemangioblastomas that proliferate at the same rate as the malignant meningiomas. Furthermore, the multiple meningiomas definitely proliferated more actively than the single ones, but a similar proliferative activity was observed in the nonrecurrent and recurrent meningiomas. Proliferation analyses might be therefore helpful for determining aggressive meningiomas and for planning adjuvant therapy in these cases.