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Meningioma
Meningioma is an extra-axial tumour of arachnoid cells, mostly benign and slow; the choice between observation, surgery and radiation depends on size, symptoms, location and WHO grade — and the extent of resection is measured on the Simpson scale.
Why it matters in the exam
The exam shows an MRI with a dura-based lesion and asks about histology and the decision. Imaging signs: a broad dural base, a dural tail, a CSF cleft between tumour and brain, homogeneous enhancement, calcification and hyperostosis of adjacent bone. Risk factors: women 2 times more often, previous cranial irradiation and NF2 (multiple meningiomas). A small incidental meningioma without symptoms — MRI follow-up; many grow slowly and only a minority become symptomatic.
According to WHO 2021: grade 1 — most tumours; grade 2 (atypical) — 4 to 19 mitoses per 10 high-power fields, or brain invasion, or 3 of 5 features: sheeting, small cells, prominent nucleoli, hypercellularity and spontaneous necrosis; the chordoid and clear cell types are grade 2. Grade 3 (anaplastic) — 20 or more mitoses per 10 fields, carcinoma-like or sarcoma-like appearance, or a TERT promoter mutation or homozygous CDKN2A/B deletion. The Simpson scale: 1 — complete removal including dura and bone; 2 — complete removal with coagulation of the dura; 3 — no treatment of the dura; 4 — subtotal removal; 5 — decompression or biopsy only. When the tumour invades a patent sagittal sinus, residual tumour is left on the sinus and treated with radiosurgery. In the cerebellopontine angle a meningioma differs from a schwannoma by a broad dural base, an obtuse angle with the petrous bone, a position eccentric to the internal auditory canal and calcification — whereas a schwannoma enters the canal and widens it.
Key points
- Extra-axial, dural tail, hyperostosis.
- WHO: 4 to 19 mitoses or brain invasion — grade 2; 20 or more — grade 3.
- Simpson 1 to 5 describes the extent of resection.
- Incidental and small — observe; growing or symptomatic — operate.
- Grade 3 — radiation always.
Summary table
| WHO grade | Main criteria | Treatment after surgery | Note |
|---|---|---|---|
| 1 | Fewer than 4 mitoses per 10 fields, no brain invasion | Observation | Most meningiomas |
| 2 (atypical) | 4 to 19 mitoses, brain invasion, or 3 of 5 features; chordoid, clear cell | Radiation after subtotal removal; consider after complete | Higher recurrence rate |
| 3 (anaplastic) | 20 or more mitoses, anaplasia, TERT or CDKN2A/B | Radiation always | Poor prognosis |
| Small incidental without symptoms | — | MRI follow-up | Radiosurgery for a growing tumour under 3 cm |
A free exam question
איזה מההיגדים הבאים, המתייחסים ל- meningioma sheath nerve ,optic נכון? (the question as examined, in Hebrew)
- א. גידולים אלו בדרך כלל אינם דינאמיים )לא גדלים( ואינם מצריכים טיפול
- ב. בחולה שאובחן עם הגידול בגין פפילאדמה ו- defect pupillary afferent relative בדרגה +2 ישנה התוויה לכריתה ניתוחית של הגידול על מנת לשמר את עצב הראייה
- ג. טיפול הבחירה בגידול שהתגלה באופן אקראי, בהינתן שלא אובחנה פגיעה בעצב הראייה, הינו )fractionated .radiation therapy (FRP
- ד. בגידול עם התפשטות תוך קרנאלית ולחץ על הכיאזמה ישנה התוויה לכריתה ניתוחית על מנת למנוע נזק לעצב הראייה הנגדי
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Sources
- WHO Classification of Tumours: Central Nervous System Tumours, 5th edition (2021) — Meningiomas
- EANO guideline on the diagnosis and management of meningiomas, 2021 — Treatment by grade and location
- Youmans and Winn Neurological Surgery, 8th edition (2022) — Meningiomas
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.