Diffuse astrocytoma:

(Grade II)

1. 
   

   Young adults presenting with seizures

   
   
2. 
   

   Focal neurologic deficits are less common (compared to high grade lesions)

   
   
3. 
   

   May be an incidental finding (investigating trauma, headache etc.)

   
   
4. 
   

   They represent 20% of astrocytomas

1. 
   

   Imaging:

   
   
   
   
   1. 
      

      MRI: ↑ intensity in T2 weighted images. Typically a frontal lobe lesion with no or minimal enhancement

      
      
   2. 
      

      CT: ↓ density

   
   
2. 
   

   Histology: nuclear atypia and pleomorphism

Subtypes of diffuse astrocytomas:

1. 
   

   Fibrillary (most common)

   
   
2. 
   

   Gemistocytic (> 20 gemistocytic cells per high power field associate with worse prognosis)

   
   
3. 
   

   Protoplasmic

Mainstay of treatment is:

1. 
   

   Maximal Surgical resection that can be safely accomplished. Consider awake craniotomy for lesions involving eloquent brain. Early resection is superior to biopsy and observation (5-y survival rate of 74 vs. 60%) ¹ and should be preferred even for incidental findings ²

   
   
2. 
   

   Radiation therapy. Dose: 50 Gy in 2-Gy fractions over 6 wk. There is data suggesting that postoperative (early) radiation prolongs progression-free survival but does not prolong overall survival. ³ May choose not to give adjuvant radiation post-op in patients who fulfill several of the following criteria:

   
   
   
   
   • 
     

     Age < 40 y

     
     
   • 
     

     Lesion not crossing midline

     
     
   • 
     

     Initial tumor size < 5 cm

     
     
   • 
     

     No pre-op neuro deficit

     
     
   • 
     

     Gross total resection with isocitrate dehydrogenase (IDH) mutation

   
   

   If adjuvant radiation is not given, then perform very close follow-up.

   
   

   Prognosis:

   
   
   
   
   1. 
      

      More favorable for:

      
      
      
      
      • 
        

        Gross total resection

        
        
      • 
        

        Young age (< 40 y)

        
        
      • 
        

        Karnofsky’s performance score > 80

        
        
      • 
        

        Location in noneloquent brain

        
        
      • 
        

        Maximal tumor diameter < 4 cm

        
        
      • 
        

        Mutations in IDH1 and IDH2

      
      

      If above criteria are met, then a 5-y survival rate of 97% may be expected. ⁴

      
      
   2. 
      

      Five-year survival rate:

      
      
      
      
      • 
        

        Gross total resection: 70%

        
        
      • 
        

        Subtotal resection: 40%

      
      
   3. 
      

      Overall median survival is 8 y

      
      
   4. 
      

      Recurrent tumor may be of the same or higher grade (III or IV) compared with initial tumor. Treat with:

      
      
      
      
      • 
        

        Surgical re-resection if possible, particularly in the presence of mass effect

        
        
      • 
        

        Radiation therapy if it had not been administered initially or significant time has passed since administration

        
        
      • 
        

        Chemotherapy may be a good option for those who have not received it before. Investigative clinical treatment protocols may be preferable for patients having previously received chemotherapy.

Treatment options for anaplastic astrocytomas (grade III) and glioblastomas (grade IV) are the same

Current treatment for patients < 70 y is surgery PLUS radiation PLUS chemotherapy

1. 
   

   Open surgery is preferred when gross total resection is possible. Partial resection carries risk of postoperative hemorrhage and edema and there is no survival benefit. ⁵ Gross total resection is associated with improved survival. ⁶

   
   
2. 
   

   Stereotactic biopsy should be preferred when:

   
   
   
   
   • 
     

     Gross total resection cannot be safely achieved

     
     
   • 
     

     Elderly patients, usually those older than 70 y (young age is the most important positive prognostic factor)

     
     
   • 
     

     Karnofsky’s performance scale < 70

     
     
   • 
     

     Multiple lesions

   
   

   Target the most suspicious region for high-grade lesion based on MRI.

   
   
3. 
   

   Radiation therapy of tumor and the margin of Increased signal in T2 weighted image (T2WI) signal ⁷ within 6 wks from surgery or biopsy Total dose is 60 Gy administered as 2 Gy for 5 d/wk for 6 wsk (30 fractions)

   
   
4. 
   

   Chemotherapy: Temozolomide: (alkylating agent)

   
   
   
   
   1. 
      

      Within 6 wks from surgery or biopsy.

      
      
   2. 
      

      Dose ⁸ : 75 mg/m²/d until the completion of radiation therapy

      
      
   3. 
      

      A month after the end of radiation therapy, initiate 5d of daily treatment every 4 wks for a total of 6 cycles with 150 to 200 mg/m²/d

   
   

   Possible side effect: myelosuppression.

   
   

   Methylation of O ⁶ -methylguanine-DNA methyltransferase (MGMT) gene is a good prognosticator for tumor response to temozolomide

   
   
5. 
   

   Recurrence:

   
   
   
   
   1. 
      

      Consider surgical resection if it can be safely performed and Karnofsky’s performance scale is > 70

      
      
   2. 
      

      Carmustine-impregnated wafers, placed in tumor bed, marginally increase survival but have a high complication rate (wound healing, malignant edema, etc.). May be considered for recurrence if not already used in primary resection. ⁹

      
      
   3. 
      

      Consider stereotactic radiosurgery for patients with no indication for surgery

      
      
   4. 
      

      Consider chemotherapy (temozolomide or other agents)

   
   
6. 
   

   Prognosis: For both grades III and IV, prognosis is more favorable for:

   
   
   
   
   1. 
      

      Gross total resection

      
      
   2. 
      

      age < 50 y

      
      
   3. 
      

      MGMT gene methylation (predicts response to alkylating chemotherapy)

      
      
   4. 
      

      IDH1 and IDH2 gene mutations

Overall prognosis:

• 
  

  Anaplastic astrocytoma: median survival 2–3 y

  
  
• 
  

  GBM:

  
  
  
  
  1. 
     

     IDH wild-type GBM (typically de novo -90% of cases): median survival (with complete treatment) 15 mo. ¹⁰

     
     
  2. 
     

     IDH-mutant GBM (usually history of prior low grade glioma and younger age: 10% of cases): median survival (with complete treatment) 31 mo. ¹⁰

Glioblastoma:

(Grade IV)

1. 
   

   The most common primary tumor of brain with mean patient age at presentation: ~55 y for de novo lesion and ~45 y for progression from lower grade

   
   
2. 
   

   50% of astrocytomas

   
   
3. 
   

   Multifocal in 5%

   
   
4. 
   

   Rarely:

   
   
   
   
   • 
     

     CSF dissemination

     
     
   • 
     

     Metastases

   
   
5. 
   

   “Butterfly glioma”: invasion of contralateral hemisphere through corpus callosum

1. 
   

   MRI: typically deep frontotemporal lesion with irregular enhancement

   
   
2. 
   

   Histology: microvascular proliferation, necrosis

1. 
   

   Subtypes:

   
   
   
   
   • 
     

     Giant cell GBM (better prognosis)

     
     
   • 
     

     Gliosarcoma: 2% of GBMs typically in temporal lobe with sarcoma component and metastases

     
     
   • 
     

     Epithelioid GBM

   
   
2. 
   

   Genetic syndromes associated with GBM:

   
   
   
   
   1. 
      

      Turcot’s

      
      
   2. 
      

      Li–Fraumeni

      
      
   3. 
      

      Neurofibromatosis 1 (NF1)

Subependymoma

(Grade I)

1. 
   

   Patient are 40–60 y of age

   
   
2. 
   

   Typically asymptomatic

   
   
3. 
   

   may present due to obstructive hydrocephalus

1. 
   

   Small, usually < 2 cm (vs. subependymal giant cell astrocytomas, which are typically large)

   
   
2. 
   

   Location frequency:

   
   
   
   
   • 
     

     4th ventricle in 60%

     
     
   • 
     

     Lateral ventricles in 40%

   
   
3. 
   

   No enhancement or edema in MRI (isointense on T1WI and hyperintense on T2WI)

   
   
4. 
   

   Histology: epithelial membrane antigen (EMA) negative (vs. positive in ependymomas)

1. 
   

   Close follow-up in asymptomatic patients

   
   
2. 
   

   Treat hydrocephalus if present

   
   
3. 
   

   Surgical resection is uncommon and is reserved for symptomatic mass effect and growing lesions with atypical behavior

Prognosis: excellent. A very slowly growing lesion that usually remain asymptomatic

1. 
   

   Pediatric patients:

   
   
   
   
   • 
     

     Posterior fossa lesion (floor of the 4th ventricle)

     
     
   • 
     

     Hydrocephalus with subsequent ↑ICP and cranial nerves palsies (CNVI, VII)

   
   
2. 
   

   Adults:

   
   
   
   
   • 
     

     intramedullary spinal lesion: The subtype presenting in the filum is typically of myxopapillary histology and is a much more benign variant (grade I).

     
     
   • 
     

     It may also present, less commonly, as a supratentorial lesion frequently with cystic component

   
   
3. 
   

   “Drop metastasis” (spine) may present along with the cranial lesion and should be ruled out

   
   
4. 
   

   Associated with NF2

1. 
   

   MRI of entire neuraxis to exclude seeding.

   
   
2. 
   

   Lesion may be:

   
   
   
   
   • 
     

     lobulated

     
     
   • 
     

     cystic

     
     
   • 
     

     with calcifications

     
     
   • 
     

     with varying enhancement

   
   
3. 
   

   Lesions rarely may also present outside the CNS (mediastinum, ovaries and other)

   
   
4. 
   

   Histology: Glial fibrillary acidic protein (GFAP) positive (vs. choroid plexus papillomas and metastatic carcinomas that are negative)

1. 
   

   Grade II variants:

   
   
   
   
   1. 
      

      Cellular

      
      
   2. 
      

      Papillary (“classic form”)

      
      
   3. 
      

      Clear cell

      
      
   4. 
      

      Tanycytic

   
   
2. 
   

   Myxopapillary ependymoma of the filum is a grade I lesion)

1. 
   

   Surgical resection is the mainstay both for cranial and spinal lesions. Extent of resection affects survival. ¹³ Due to frequent invasion of obex, complete resection is often impossible in children.

   
   
2. 
   

   Radiation: For patients with cranial lesions, who are older than 3 y include:

   
   
   
   
   1. 
      

      Fractionated radiation at resection bed

      
      
   2. 
      

      Spinal radiation in case of drop metastasis. Ependymomas are very radiosensitive. Spinal ependymomas (both intramedullary and myxopapillary of the filum) are typically cured via surgery and do not require radiation

   
   
3. 
   

   For cranial lesions, consider:

   
   
   
   
   • 
     

     postoperative (2 wks postop) lumbar puncture for CSF cytology or

     
     
   • 
     

     MRI of neuraxis to exclude drop metastasis

Prognosis:

5-y survival:

1. 
   

   Pediatric patients 30%

   
   
2. 
   

   Adults near 80%

   
   
3. 
   

   Myxopapillary > 95%

Chemotherapy could be considered as a treatment option for ependymomas in order to delay radiation therapy in very young children. ¹⁵

Atypical choroid plexus papilloma

(Grade II)

As above

1. 
   

   MRI: similar to choroid plexus papilloma + possibly hemorrhage-necrosis

   
   
2. 
   

   Histology: Two or more mitoses per 10 high-power fields (related to recurrence)

Surgical resection

Prognosis:

• 
  

  Higher recurrence rate as compared to grade I lesions

  
  
• 
  

  Intermediate 5-y survival rate between grade I and III lesions

For all the above tumors:

80% of choroid plexus tumors present in children < 2 y of age

For all the above tumors:

1. 
   

   Imaging cannot reliably distinguish between different grades

   
   
2. 
   

   Perform preoperatively MRI of entire spine (there is risk of CSF seeding, higher with grade III lesions)

For all the above tumors:

Associated with:

• 
  

  Li–Fraumeni syndrome

  
  
• 
  

  Aicardi’s syndrome

For all the above tumors:

1. 
   

   Always consider surgery for residual tumor or recurrence

   
   
2. 
   

   Possible complication: postoperative subdural collections (fistula between ventricles and subdural space) that may require shunting

   
   
3. 
   

   Hydrocephalus may not resolve completely postoperatively.

Ganglioglioma:

(GRADE I)

Children and young adults with seizures and temporal lobe lesion

Frequently cystic lesion with enhancing mural nodule and calcifications

Neuronal (ganglion) + astrocytic (glial) cells: some correlate prognosis with the astrocytic component

Surgical resection

Prognosis: 10-y survival rate of 85%

Central neurocytoma:

(Grade II)

1. 
   

   Young adults with large ventricles

   
   
2. 
   

   Symptoms of ↑ICP

1. 
   

   MRI and CT:

   
   
   
   
   1. 
      

      “Bubbly” lesion originating in septum pellucidum, within the lateral and 3rd ventricles in the vicinity of foramen of Monro

      
      
   2. 
      

      Contrast enhancement

      
      
   3. 
      

      Usually calcifications

   
   
2. 
   

   Histology: “Fried egg” cell appearance similar to oligodendroglioma, but no IDH mutations or 1p19q deletions

1. 
   

   Surgical resection: The 2-year and 4-year recurrence rates in pts w/ MIB-1 labeling >4% are 50% and 75% respectively

   
   
2. 
   

   Stereotactic radiosurgery if MIB-1 is elevated (> 2%) and no gross total resection has been achieved

   
   
3. 
   

   Chemotherapy in recurrence and inoperable tumors

Prognosis: complete surgical resection is a cure.

Medulloblastomas:

(Grade IV)

1. 
   

   Typically pediatric pts (peak age: 7 y) and young adults with lesion arising from:

   
   
   
   
   • 
     

     the roof of the 4th ventricle (vs. ependymoma arising from floor)

     
     
   • 
     

     in cerebellar hemisphere (older children, adults)

   
   
2. 
   

   May present with:

   
   
   
   
   1. 
      

      Hydrocephalus

      
      
   2. 
      

      ↑ ICP signs

      
      
   3. 
      

      Gait disturbance and

      
      
   4. 
      

      Truncal ataxia

   
   
3. 
   

   Frequently drop metastases (up to 1/3 of cases)

   
   
4. 
   

   Rarely metastases (higher frequency with large cell subtype)

   
   
5. 
   

   Preterm children are at increased risk

1. 
   

   MRI:

   
   
   
   
   • 
     

     T2WI: heterogeneous

     
     
   • 
     

     DWI: restricted diffusion

     
     
   • 
     

     significant contrast enhancement

   
   
2. 
   

   CT: hyperdense lesion

   
   
3. 
   

   MRI of entire spine with contrast to rule out drop metastases preoperatively or at least 2–3 wk postoperatively (not earlier because of blood)

   
   
4. 
   

   Histology: “Small round blue cell neoplasm”

1. 
   

   Most common malignant pediatric brain tumor

   
   
2. 
   

   Based on molecular subgroup (medulloblastomas genetically defined: WHO classification 2016) ²⁰ :

   
   
   
   
   • 
     

     Medulloblastoma WNT

     
     
   • 
     

     Medulloblastoma SHH

     
     
   • 
     

     Medulloblastoma Group 3

     
     
   • 
     

     Medulloblastoma Group 4

1. 
   

   Surgical resection:

   
   
   
   
   1. 
      

      Lesion on the 4th ventricle floor and brainstem is not resected to prevent poor neurological outcome

      
      
   2. 
      

      Consider external ventricular drain (EVD) preoperatively

   
   

   REMEMBER:

   
   
   
   
   1. 
      

      Gross total resection: no residual tumor

      
      
   2. 
      

      Near-total resection: < 1.5 cm² residual tumor

      
      
   3. 
      

      Subtotal resection: > 1.5 cm² residual tumor

   
   
2. 
   

   Lumbar puncture for cytology before craniotomy if no hydrocephalus

   
   
3. 
   

   Consider treatment of hydrocephalus (shunt carries a risk of seeding)

   
   
4. 
   

   Craniospinal radiation therapy for age > 3 y:

   
   
   
   
   • 
     

     Dose: 10–15 Gy to tumor bed and 35–40 Gy to neuraxis over 6 wks

     
     
   • 
     

     Consider lower dose to neuraxis after gross total resection

   
   
5. 
   

   Chemotherapy (lomustine, vincristine, cisplatin):

   
   
   
   
   • 
     

     Children < 3 y

     
     
   • 
     

     Residual tumor > 1.5 cm²

     
     
   • 
     

     Metastases

     
     
   • 
     

     Recurrence

Prognosis

1. 
   

   Prognosis worse for:

   
   
   
   
   • 
     

     Male patient

     
     
   • 
     

     Residual tumor > 1.5 cm²

     
     
   • 
     

     Age < 3 y

     
     
   • 
     

     Metastases

     
     
   • 
     

     Loss of 17q, amplification of c-myc and ERBB2 overexpression

   
   
2. 
   

   Prognosis based on WHO classification:

   
   
   
   
   • 
     

     Medulloblastoma: WNT EXCELLENT (90% long-term survival LTS)

     
     
   • 
     

     Medulloblastoma: SHH GOOD: (60–85% LTS as long as no TP53 mutation)

     
     
   • 
     

     Medulloblastoma: Group 3 POOR: (< 50% LTS)

     
     
   • 
     

     Medulloblastoma: Group 4 GOOD: (75% LTS)

ERBB2-protein negative tumors have a better prognosis

Patients at the 4th–6th decade of life with:

1. 
   

   Ipsilateral sensorineural loss of hearing (high-tone loss and difficulty in discriminating words)

   
   
2. 
   

   High-pitched tinnitus

   
   
3. 
   

   Disequilibrium

   
   
4. 
   

   Tumor > 2 cm may also present with (compression of adjacent structures):

   
   
   
   
   • 
     

     Facial numbness

     
     
   • 
     

     Facial weakness (usually late symptom)

     
     
   • 
     

     Otalgia

     
     
   • 
     

     Brainstem symptoms

     
     
   • 
     

     Dysgeusia

     
     
   • 
     

     Lower cranial nerve

     
     
   • 
     

     symptoms

     
     
   • 
     

     Hydrocephalus (tumor > 4 cm)

     
     
   • 
     

     Represents 80% of CPA tumors. Second most common is meningioma.

     
     
   • 
     

     NF2:

1. 
   

   Bilateral vestibular Schwannomas

   
   
2. 
   

   An early diagnosis of vestibular schwannoma (< 40 y of age) should initiate investigation on possible coexistence of NF2

1. 
   

   MRI brain:

   
   
   
   
   • 
     

     Lesion presents heterogeneous enhancement and may be cystic

     
     
   • 
     

     When large: “ice cream on cone” shape

     
     
   • 
     

     When small: “filling defect” within the increased signal CSF of internal acoustic canal (high-resolution T2WI)

   
   
2. 
   

   CT brain: enlarged internal auditory meatus (normal diameter: 5–8 mm). Meningiomas cause hyperostosis and decrease of the diameter of the internal auditory canal

   
   
3. 
   

   Audiometric tests:

   
   
   
   
   1. 
      

      Pure-tone audiogram

      
      
   2. 
      

      Speech discrimination

      
      
   3. 
      

      When the lesion is small (< 1.5 cm):

      
      
      
      
      • 
        

        ENG (electronystagmography) for superior vestibular nerve

        
        
      • 
        

        VEMP (vestibular evoked myogenic potential) for inferior vestibular nerve

        
        
      • 
        

        ABR (auditory brain responses): prognosis for preservation of hearing

   
   
4. 
   

   Histology:

   
   
   
   
   1. 
      

      Antoni A pattern (cellular, fibrillary elongated appearing tissue)

      
      
   2. 
      

      Antoni B pattern (less cellular microcystic tissue)

1. 
   

   It is a grade I lesion presenting in the CPA and arising from Schwann cells of the superior division of the vestibular nerve (transition zone between central and peripheral myelination).

   
   
2. 
   

   The 2nd most common intracranial schwannoma is from trigeminal nerve

   
   
3. 
   

   Associated with loss of a tumor suppressor gene on the long arm of chromosome 22

   
   
4. 
   

   Facial nerve is displaced anteriorly (75% of cases), followed (in frequency) by superiorly, inferiorly, posteriorly

   
   
5. 
   

   “50/50 rule” to define serviceable hearing:

   
   
   
   
   • 
     

     pure-tone audiogram threshold ≤ 50 dB

     
     
   • 
     

     speech discrimination score ≥ 50%

1. 
   

   Tumors < 1.5 cm with perfect hearing: consider close follow-up

   
   

   REMEMBER:

   
   
   
   
   1. 
      

      No further growth is expected if no growth has been documented in the first 5 y from diagnosis

      
      
   2. 
      

      60% of vestibular schwannomas are slow growing (< 1 mm/y)

   
   
2. 
   

   Tumors < 1.5 cm with serviceable hearing:

   
   
   
   
   1. 
      

      Close follow-up

      
      
   2. 
      

      Stereotactic radiosurgery

   
   
3. 
   

   Tumors > 1.5 cm:

   
   
   
   
   1. 
      

      Stereotactic radiosurgery for:

      
      
      
      
      • 
        

        Lesions up to 3 cm with no mass effect

        
        
      • 
        

        Residual post-op lesions (12–16 Gy, depending on weather hearing is serviceable)

      
      
   2. 
      

      Consider fractionated radiotherapy for even larger lesions with no mass effect and significant patient comorbidity

   
   

   Approximately 18–24 mo are necessary for radiation therapy to present its full effect

   
   

   Surgery vs. radiation therapy:

   
   
   
   
   1. 
      

      Radiation therapy appears to be superior to surgery at preserving hearing (particularly when dose to 50% isodose is kept below 13 Gy)

      
      
   2. 
      

      Surgery is superior at controlling vertigo/disequilibrium

      
      
   3. 
      

      Their results appear comparable for:

      
      
      
      
      • 
        

        Facial nerve preservation

        
        
      • 
        

        Trigeminal nerve function

        
        
      • 
        

        Tumor control (a temporary increase in dimension may be observed with radiation therapy)

   
   
4. 
   

   Tumors > 3 cm or with symptoms of mass effect:

   
   

   Surgery (always with intraoperative monitoring). Choice of approach depends on several factors including:

   
   
   
   
   • 
     

     Tumor size

     
     
   • 
     

     Tumor anatomy

     
     
   • 
     

     Hearing in ipsilateral ear

     
     
   • 
     

     Hearing in contralateral ear

     
     
   • 
     

     Surgeon preference

   
   

   Surgical approaches:

   
   
   
   
   1. 
      

      Retrosigmoid:

      
      
      
      
      • 
        

        Good for hearing preservation

        
        
      • 
        

        Wide angle of view

        
        
      • 
        

        Beware of cerebellar retraction

        
        
      • 
        

        Not good for purely intracanalicular tumors

      
      
   2. 
      

      Translabyrinthine:

      
      
      
      
      • 
        

        No preservation of hearing

        
        
      • 
        

        Superior facial nerve preservation

        
        
      • 
        

        Excellent for avoiding cerebellar retraction in large tumors

      
      
   3. 
      

      Subtemporal:

      
      
      
      
      • 
        

        Improved hearing preservation

        
        
      • 
        

        Slight increase in facial nerve palsy. Facial nerve encountered first in this approach

        
        
      • 
        

        Excellent approach for purely intracanalicular tumors

Meningioma:

(Grade I)

Subtypes:

• 
  

  Meningothelial (syncytial): the most common

  
  
• 
  

  Fibrous (fibroblastic)

  
  
• 
  

  Transitional

  
  
• 
  

  Psammomatous

  
  
• 
  

  Angiomatous: abundant blood vessels

  
  
• 
  

  Microcystic: may present cysts having an atypical radiologic presentation)

  
  
• 
  

  Secretory: significant perilesional edema that may complicate treatment

  
  
• 
  

  Lymphoplasmacyte-rich meningioma: significant lympho-plasmacytic infiltrates in the tumor and clinical presentation that resembles an inflammatory process with peripheral blood abnormalities

  
  
• 
  

  Metaplastic: mesenchymal differentiation of various extent (bone, cartilage, fat may be observed)

1. 
   

   Very common (15%) primary intracranial tumor presenting usually in female adults

   
   
2. 
   

   Presentation

   
   
   
   
   1. 
      

      Frequently asymptomatic

      
      
   2. 
      

      Neurological deficit depending on location

      
      
   3. 
      

      Seizures (supratentorial tumor)

      
      
   4. 
      

      Foster–Kennedy syndrome in olfactory groove meningiomas (anosmia + ipsilateral optic atrophy + contralateral papilledema)

   
   
3. 
   

   Multiple meningiomas are associated with NF2

1. 
   

   MRI:

   
   
   
   
   • 
     

     dural-based enhancing lesion with variable edema.

     
     
   • 
     

     T1WI: isointense

     
     
   • 
     

     T2WI: hyper or isointense

     
     
   • 
     

     “Dural tail” (which may also be observed in pleomorphic xanthoastrocytoma)

   
   

   REMEMBER: Check patency of dural sinuses (consider MRV-based on location of lesion)

   
   
2. 
   

   CT: hyperostosis of adjacent bone and calcification of lesion may be present

   
   
3. 
   

   Digital subtraction angiography (DSA):

   
   
   
   
   • 
     

     May be needed based on anatomic location and/or for pre-op embolization

     
     
   • 
     

     “Sunburst” or radial appearance. Enhancement presents in early arterial phase and persists (“come early, stay late”)

     
     
   • 
     

     External carotid artery feeders with the exception of:

     
     
     
     
     1. 
        

        Olfactory groove (fed by the ethmoidal branches of ophthalmic artery, which is a branch of ICA)

        
        
     2. 
        

        Supra and parasellar lesions

   
   
4. 
   

   Frequent anatomic locations (90% are supratentorial):

   
   
   
   
   • 
     

     Adults:

     
     
     
     
     1. 
        

        Parasagittal: Grading for meningioma invasion of superior sagittal sinus ²² :

        
        
        
        
        • 
          

          Type I: attachment to lateral wall of sinus

          
          
        • 
          

          Type II: lateral recess invasion

          
          
        • 
          

          Type III: lateral wall invasion

          
          
        • 
          

          Type IV: lateral wall and roof invasion

          
          
        • 
          

          Type V: total occlusion of sinus with contralateral wall spared

          
          
        • 
          

          Type VI: total occlusion with invasion of all walls

        
        
     2. 
        

        Convexity

        
        
     3. 
        

        Tuberculum sellae (chiasmal syndrome: optic atrophy + bitemporal hemianopsia)

        
        
     4. 
        

        Sphenoidal ridge:

        
        
        
        
        • 
          

          Pterional or lateral third

          
          
        • 
          

          Alar or middle third

          
          
        • 
          

          Clinoidal or medial third

     
     

     Multiple meningiomas in 9% of pts (frequently associated with history of radiation or NF2).

     
     
   • 
     

     Children:

     
     
     
     
     1. 
        

        Intraventricular

        
        
     2. 
        

        Posterior fossa

   
   
5. 
   

   Rare anatomic locations:

   
   
   
   
   1. 
      

      Intraosseous (skull)

      
      
   2. 
      

      Subcutaneous

   
   
6. 
   

   Metastases (lung, liver, lymph nodes, heart): usually grade III meningiomas

   
   
7. 
   

   Consider hemangiopericytoma if the lesion is growing more rapidly than expected

   
   
8. 
   

   Histology: psammoma bodies (calcified whorls)

   
   
9. 
   

   Immunohistochemical stains:

   
   
   
   
   1. 
      

      EMA

      
      
   2. 
      

      Vimentin

1. 
   

   They arise from arachnoid meningothelial “cap” cells

   
   
2. 
   

   Genetics:

   
   
   
   
   1. 
      

      Monosomy 22 (up to 70% of tumors)

      
      
   2. 
      

      1p and 14q deletions (associated with more aggressive behavior)

      
      
   3. 
      

      Association with NF2

   
   
3. 
   

   Associated with radiation

1. 
   

   Follow up for:

   
   
   
   
   1. 
      

      Asymptomatic tumor

      
      
   2. 
      

      No progressive growth

      
      
   3. 
      

      Low life expectancy

      
      
      
      
      • 
        

        After first diagnosis, repeat MRI after 3–4 mo (to exclude rapid growth) and then follow annually for 3 y.

        
        
      • 
        

        Pregnancy and breast cancer may cause growth.

   
   
2. 
   

   Surgical resection for:

   
   
   
   
   1. 
      

      Symptomatic

      
      
   2. 
      

      lesions with progressive growth

   
   

   Surgical technique:

   
   
   
   
   1. 
      

      Consider preoperative embolization with particulate agents

      
      
   2. 
      

      Deprive early the tumor of its blood supply

      
      
   3. 
      

      Internal decompression maintaining the capsule (“if you can debulk, you should debulk”)

      
      
   4. 
      

      Avoid healthy brain retraction

      
      
   5. 
      

      Drill (remove) any attached bone

      
      
   6. 
      

      Maintain venous drainage:

      
      
      
      
      • 
        

        Superior sagittal sinus can usually be safely occluded anterior to coronal suture but never posteriorly to the vein of Trolard

        
        
      • 
        

        The dominant transverse sinus should be preserved

      
      

      It is safer to:

      
      
      
      
      • 
        

        Leave residual tumor in sinus than sacrifice sinus

        
        
      • 
        

        Close follow-up of remnant

        
        
      • 
        

        Stereotactic radiosurgery in case of growth

   
   
3. 
   

   Consider focal radiation therapy/radiosurgery:

   
   
   
   
   1. 
      

      For tumors < 3 cm

      
      
   2. 
      

      For patients with contraindication to surgery

      
      
   3. 
      

      For surgically inaccessible lesion

      
      
   4. 
      

      For growing residual tumor

      
      
   5. 
      

      After recurrence

      
      
   6. 
      

      For atypical or anaplastic meningioma after surgical resection

REMEMBER: Stereotactic radiosurgery has overall disease stabilization rate of 89% and complication rate of 7% ²³

Prognosis:

• 
  

  Most important for preventing recurrence is extent of resection

  
  
• 
  

  Ki-67/MIB-1 inversely correlates with prognosis

  
  
• 
  

  Worse prognosis for:

  
  
  
  
  1. 
     

     1p and 14q deletions

     
     
  2. 
     

     Lack of progesterone receptors are associated with more aggressive behavior

Atypical meningioma

(Grade II)

Other grade II meningiomas:

• 
  

  Chordoid

  
  
• 
  

  Clear cell: young adults with lesion in spinal canal or posterior fossa

5% of meningiomas

• 
  

  Brain invasion and mitotic count of 4 or more/10 high-power fields. ¹⁰

  
  
• 
  

  Can also be diagnosed based on the presence of 3 out of 5 of the subsequent features:

  
  
  
  
  1. 
     

     Spontaneous necrosis

     
     
  2. 
     

     Sheeting (loss of whorling or fascicular architecture)

     
     
  3. 
     

     Prominent nucleoli

     
     
  4. 
     

     High cellularity

     
     
  5. 
     

     Small cells (clusters with high nuclear-to-cytoplasmic ratio) ¹⁰

1. 
   

   Surgical resection

   
   
2. 
   

   Radiation therapy after both total and subtotal resection. ²⁵

Prognosis:

1. 
   

   5-y survival rate of 30%

   
   
2. 
   

   Metastases in 5% of cases