PROLIFERATION POTENTIAL AND HISTOLOGICAL FEATURES IN NEUROFIBROMATOSIS 2-ASSOCIATED AND SPORADIC MENINGIOMAS

The authors compared the histological appearance and proliferation pot ential of 35 meningiomas in patients with neurofibromatosis 2 (NF2) an d 30 sporadic meningiomas in age- and gender-matched patients without NF2. The NF2 meningiomas showed more mitotic figures (p < 0.001) and n uclear pleomorphism (p = 0.003) that the sporadic meningiomas; however , the incidence of meningothelial, fibroblastic, and transitional subt ypes occurred equally in both groups. The proliferation potential was significantly higher in the 35 meningiomas removed from 23 patients wi th NF2 than in the 30 sporadic meningiomas removed in the 30 patients without NF2 (mean MIB-1 labeling indices: 2.5 vs. 1.75. p = 0.0147). T he higher proliferation potential of the NF2 meningiomas may reflect d ifferences in molecular biology between sporadic and NF2 meningiomas a nd may be related to an earlier onset, multiplicity. and more aggressi ve behavior of NF2 tumors.