Sporadic Meningioma [Neurosurgery Wiki]

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====== Sporadic Meningioma ======

A **sporadic meningioma** is a meningioma that arises **without a known hereditary or familial predisposition**. These tumors develop **de novo**, typically as **isolated lesions**, and account for the majority of meningioma cases in the general population.

===== 🧠 Definition =====
A **meningioma** is a primary central nervous system tumor that arises from the **arachnoid cap cells** of the meninges. When it occurs **outside the context of genetic syndromes** such as neurofibromatosis type 2 (NF2), it is classified as **sporadic**.

===== 📊 Epidemiology =====
  * Represents ~80–90% of all meningiomas.
  * More common in **women**.
  * Typically occurs in **middle-aged to older adults**.
  * Risk factors may include **age**, **ionizing radiation**, and **hormonal influences**.

===== 🧬 Molecular Features =====
  * **NF2 gene mutation or 22q deletion**: common in sporadic **grade I and II** meningiomas.
  * **Non-NF2 mutations**: TRAF7, KLF4, AKT1, SMO, and PIK3CA — associated with specific histological subtypes and locations.
  * Typically lacks germline mutations found in familial syndromes.

===== 🧠 Clinical Presentation =====
  * Often asymptomatic, discovered incidentally.
  * Symptoms depend on tumor size and location:
    * Headache
    * Seizures
    * Focal neurological deficits
    * Visual changes, depending on location

===== 🧪 Diagnosis =====
  * **Neuroimaging**: MRI with contrast (gold standard)
  * **Histopathological confirmation** after surgical resection
  * **Molecular profiling** increasingly used for classification and prognosis

===== ⚕️ Treatment =====
  * Observation for small, asymptomatic tumors
  * **Surgical resection** (Simpson grade I-II ideal)
  * **Radiotherapy** (e.g., stereotactic radiosurgery) for residual or inoperable cases
  * Ongoing trials for **targeted therapies** in selected molecular subtypes

===== 🔄 Differential Diagnosis =====
  * Familial or syndromic meningiomas (e.g., NF2-related)
  * Hemangiopericytoma / Solitary fibrous tumor
  * Dural metastasis

===== 🧷 Related Pages =====
  * [[meningioma]]
  * [[nf2_mutation]]
  * [[nf2_alteration]]
  * [[merlin_protein]]
  * [[meningioma_molecular_classification]]