The influence of age on the histological grading of meningiomas.

This study was undertaken to assess the relationship between the age of patients at the time of their surgery and histological grading of meningiomas. A retrospective review was conducted for 1,083 consecutive patients with meningiomas who had surgical removal between January 1991 and December 2006. Histological grading for each tumor was done utilizing the WHO classification for meningiomas. The incidence of WHO grade II or III tumors between the elderly and the non-elderly groups was compared. The mean age at diagnosis for the WHO grade I, II, and III tumors was 55.1 (±14.79), 59.0 (±15.54), and 64.3 years (±13.28) (p value = 0.007), respectively. We found that 11.9 % of meningiomas diagnosed after the age of 60 years was WHO grade II or III, while this value was only 6.9 % for patients 60 years or younger (p = 0.0006). Our study showed that the combined incidence of WHO grade II and III meningiomas increases as age advances. We believe that this constitutes an important piece of information requiring neurosurgeons to carefully and continuously observe the elderly patients harboring meningiomas.