Histopathology and MIB-1 labeling index predicted recurrence of meningiomas: a proposal of diagnostic criteria for patients with atypical meningioma.
BACKGROUND
Although various histopathologic features have been associated with aggressive behavior or recurrence of meningiomas, there is little agreement about which features are the most important and in what combination. The objective of this study was to formulate diagnostic criteria for atypical meningioma.


METHODS
Eighty-three patients with meningiomas who underwent macroscopic total resection and had been followed until they developed recurrent disease or for at least 10 years were studied. Thirteen histopathologic parameters that related to recurrence of the tumor were evaluated in each patient. All possible combinations of histologic parameters that were related significantly to recurrence were used to formulate scoring models. The model that included the fewest parameters and that could distinguish tumor recurrence best within 10 years was chosen as the final model.


RESULTS
The final model included three parameters: loss of architecture, mitoses > or= 1.5/mm2, and necrosis. Of the 52 tumors with a score < 2 (0 or 1 of the 3 parameters), all except 1 tumor did not recur within 10 years, and they were all considered benign meningiomas. Of the 31 tumors with a score > or = 2 (2 or 3 of the 3 parameters), 94% recurred within 10 years (76% recurred within 5 years), and they were considered atypical meningiomas. The estimated 5-year and 10-year recurrence rates for the benign meningiomas were 0.0% and 1.9%, respectively, for benign meningiomas and 71.0% and 93.5%, respectively, for atypical meningiomas (P < 0.001). The estimated 5-year and 10-year mortality rates also were significantly different (0.0% and 0.0% vs. 22.1% and 26.7%, respectively; P < 0.001). The MIB-1 labeling index (LI) for the entire group studied ranged from 0.4 to 33.5 (mean LI, 8.4). Fifty-two tumors with an LI of < 10 did not recur within 10 years. Of the 31 tumors with an LI > or = 10, 97% recurred (71% within 5 years).


CONCLUSIONS
Histopathology and MIB-1 LI were able to predict clinical outcomes of patients with meningioma. The authors propose that atypical meningioma may be diagnosed when two of the following three criteria are present: loss of architecture, mitoses > or = 1.5/mm2, and necrosis.
Ho
Donald Ming-Tak
DM
Department of Pathology and Laboratory Medicine, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China. mtho@vghtpe.gov.tw
Hsu
Chih-Yi
CY
Ting
Ling-Tan
LT
Chiang
Hung
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D034961:Antigens, Nuclear; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen; D008297:Male; D008577:Meningeal Neoplasms / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D008579:Meningioma / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D008938:Mitosis; D009336:Necrosis; D009364:Neoplasm Recurrence, Local; D009687:Nuclear Proteins / Q000032:analysis*; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies
D034961:Antigens, Nuclear; D019394:Ki-67 Antigen; D009687:Nuclear Proteins