The growth rate of intracranial meningiomas and its relation to histology. An analysis of 43 patients.

The growth rate of intracranial meningiomas was studied in 43 patients against a histologic grading based on the degree of anaplasia. The mean time for doubling of the tumor volume was 415 days (138-1045) in grade I (benign), 178 days (34-551) in grade II (atypical), and 205 days (30-472) in grade III (anaplastic). The difference between grade I and the combined grades II-III was highly significant. Both the mitotic index and the absence of calcification on the computed tomography scan correlated strongly with the doubling time. The growth rate should be carefully considered in planning therapy and timing computed tomography studies for patients with meningioma.