Meningiomas: Correlation of Ki67 with histological grade

Background : Meningiomas are slow-growing tumors. Grading of meningiomas based on histological features has certain limitations in predicting the exact biological behavior, necessitating ancillary techniques.
Objective : To study the Ki67 labeling index (Ki67 LI) in various histological subtypes and grades of meningioma and correlate it with various parameters for recurrence.
Material and Methods : All intracranial and intraspinal meningiomas diagnosed between 2005 and 2008 were graded according to WHO 2007 criteria. Immunohistochemistry was performed using Ki67 (Dako, USA 1:50) in 300 cases. Statistical analysis was performed.
Results : There was female predominance. The age ranged from 2-75 years including 11 children below the age of 18 years. There were 211 Grade I, 78 Grade II and 11 Grade III meningiomas. The mean Ki67 LI increased from Grade I to II and from Grade II to III and these were statistically significant. The Ki67 LI was high for the subtypes of clear cell, chordoid, papillary and rhabdoid but there was no statistical significance between the subtypes. The difference in Ki67 LI between recurrent versus non-recurrent and brain-invasive versus non-invasive meningiomas was statistically significant.
Conclusion : High Ki67 LI indicates higher grade of meningioma. The difference in KI67 LI between recurrent and non-recurrent meningiomas was statistically significant.

Keywords
Invasion, Ki67 labeling index, meningioma, recurrent, WHO 2007 criteria