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Histological characteristics of incidentally-found growing meningiomas
Hidetoshi Kasuya1, Osami Kubo, Koichi Kato
1Department of Neurosurgery, Tokyo Women's Medical University, Tokyo, Japan.
Object:
With the wider use of CT and MRI, many meningiomas are discovered as incidental findings during diagnostic work-up for unrelated symptoms. The majority shows no or minimal growth. The purpose of this study was to distinguish pathological features of incidentally-found growing meningiomas by comparing incidentally-found with symptomatic meningiomas.
Methods:
One hundred and thirty two consecutive non-recurrent surgically-treated meningiomas treated between 2005 and 2007 were divided into three categories: 19 incidentally-found growing meningiomas (IG), 50 incidentally-found meningiomas (I), and 63 symptomatic (S) meningiomas. The average follow-up period for the IG meningiomas was 3.7 years. Six out of 19 patients of the IG meningiomas became symptomatic during observation.
Results:
There is a significant difference of the incidence of WHO grades I, II, and III between all three groups (p=0.035). The incidence of WHO grades II and III in groups IG, I, and S were 26%, 2%, and 10%, respectively. We compare MIB-1 staining index between three groups: an average was 3.8% in IG, 1.3% in I, and 2.4% in S meningiomas.
Conclusions:
Incidentally-found meningiomas need careful follow-up. One fourth of the meningiomas that showed signs of growing belonged to the atypical or malignant grade.
Insights
Incidental meningiomas that grow require careful monitoring. A significant portion of these growing tumors are atypical or malignant, highlighting the need for vigilance in managing incidentally discovered meningiomas.
Area of Science:
- Neurosurgery
- Oncology
- Radiology
Background:
- Computed tomography (CT) and magnetic resonance imaging (MRI) increasingly detect meningiomas as incidental findings.
- Most incidental meningiomas exhibit minimal or no growth.
- Distinguishing pathological features of growing incidental meningiomas is crucial for appropriate management.
Purpose of the Study:
- To differentiate pathological characteristics of incidentally found growing meningiomas.
- To compare incidentally found growing meningiomas with incidentally found and symptomatic meningiomas.
Main Methods:
- A retrospective study of 132 surgically treated, non-recurrent meningiomas (2005-2007).
- Categorization into incidentally-found growing (IG, n=19), incidentally-found (I, n=50), and symptomatic (S, n=63) groups.
- Analysis of World Health Organization (WHO) grades and MIB-1 staining index.
Main Results:
- Significant differences in WHO grades I, II, and III incidence across the groups (p=0.035).
- Higher incidence of WHO grades II and III in IG (26%) compared to I (2%) and S (10%) groups.
- MIB-1 staining index was higher in IG (3.8%) than in I (1.3%) and S (2.4%) meningiomas.
Conclusions:
- Incidental meningiomas warrant close follow-up, particularly those showing growth.
- Approximately 25% of incidentally found growing meningiomas were classified as atypical or malignant (WHO grades II/III).
- These findings underscore the importance of vigilant monitoring for incidentally discovered growing meningiomas.
