GLIOMAS

•Are tumors of the CNS that arise fromglial cells

•They constitute 45% to 55%of intracranial tumors

•They are the most common tumors of the CNS

 

WHO CLASSIFICATION OF NEUROEPITHELIAL TUMORS

( World Health Organization) 

1. Astrocytic tumors•          Pilocytic astrocytoma-         Astrocytoma (fibrous gemistocytic)-          Anaplastic astrocytoma 2. Oligodendroglial tumors   Oligodendroglioma-         Mixed oligoastrocytoma-         Anaplastic oligodendroglioma 3. Tumors from ependymal cells and choroid plexus-         Ependymoma-         Anaplastic ependymoma-         Choroid plexus papilloma-         Anaplastic choroid plexus papilloma

 

4. Poorly differentiated tumors and embryonic stem cells Glioblastoma Medulloblastoma 5. Tumors of pineal cell origin Pinealoma Pinealoblastoma 6. Neuronal tumors Gangliogloioma Gangliocytoma Neuroblastoma 

KERNOHAN GRADING SYSTEM OF ASTROCYNOMAS

Grade 1Increased number of cellsEssentially of normal cytology form Pilocytic astrocytoma falls into this category

Grade 2Increased number of cells, but most of the cells are astrocytesHyperchromatic nucleiNo mitoses or necrosesFew fine vessels

Grade 3Many cells appear as astrocytesPleomorphism Few mitotic figuresNecrosis frequentlyPartial endothelial proliferation in vessels

Grade 4Few normal astrocytes appearPleomorphism prevailsMany bizarre mitosesNecroses frequentlyEndothelial proliferation in vessels prevails

ASTROCYTIC TUMORS

1) PILOCYTIC ASTROCYTOMA

Average age: 13 years

Percentage: 2% of gliomas

Localization:

- Cerebellum / strain (61%)

- Optic chiasm / hypothalamus (28%)

- Cerebral hemispheres (11%)

Clinical profile

- Chiasmal tumors : visual deficits, endocrinological dysfunctions, symptoms of hydrocephalus

- Cerebral hemispheres tumors : headache, epileptic attacks, motor deficit

Paraclinical examinations These tumors are usually cystic and have a node from solid tissue

- Head Computed Tomography : Slightly hypodense or isodense. Calcification occurs at 22%. Uptake of the injected contrast by solid tissue of the tumor.

- Magnetic resonance imaging (MRI) of the brain : By injecting  gadolinium, uptake by the solid tissue and the wall of the tumor

Treatment

- Surgical resection if possible- Total resection is rarely possible- Radiotherapy is controversial.Some doctors recommend it after subtotal resection of tumor and if the patient is older than 3

Result

- 81% survive for 10 years after subtotal resection of tumor and radiotherapy

- 54% survive for 20 years after subtotal resection of tumor and radiotherapy

HISTOLOGICAL PROFILE

- Fusiform cells with wavy fibrous processes- Rosenthal fibers are common but not essential- Eosinophilic granular particles are common- Microcystic areas of small stellate astrocytes alternate with pilocytic areas- There are macrophages, predominantly in tumors located in the cerebral hemispheres

2) LOW GRADE ASTROCYTOMA

Average age: 35 to 45 years

Percentage: 5% to 25% of gliomas

Localization: - In cerebral hemispheres, especially in the frontal lobe (40%), in the temporal lobe (25%) and parietal lobe (25%) - Other localization such as in thalamus, mesencephalon, pons (10%)

Clinical profile

- Epileptic attacks are the most frequent (65%)

- Symptoms of increased intracranial pressure (40%), personality disorders (15%), orfocal neurological deficits which are less frequent (10%)

Paraclinical examinations

- - Head Computed Tomography : Hypodense or sometimes isodense. No significant oedima appears.Rarely, uptake of the contrast

- Magnetic resonance imaging (MRI) of the brain : The lesion is usually clearly defined.Increased T2 signal. The signal ishomogeneous. Small oedema.By injecting gadolinium the image is the same asin the CT.

Treatment

-Surgical removal

-Postoperative radiotherapy iscontroversial.

- Chemotherapy is contraindicated

Result

-Average survival is around 3.5 years

-5-year survival is around 26% to 33%

-Radiotherapy prolongs life by 1 to 3 yearsbut not more.

86% of astrocytomasthat relapseare already anaplastic

Prognostic factors areage, physical condition ofthe patient and the extent of surgical resection

HISTOLOGICAL PROFILE

•Moderate polycytosis•The nuclei may appearlarge but without any significantpleomorphism•No vascular reproduction•No necrosis

3) ANAPLASTIC ASTROCYTOMA

Average age: 46 years

Percentage: 10% to 30% of gliomas

Localization:- Cerebral hemispheres, especially the frontal, temporal and parietal lobe. The rates are the same as in

low-grade astrocytomas- Thalamus, mesencephalon, pons are less likely

Clinical profile

- Epileptic attacks are the initial symptoms of at least 50% of patients- Symptoms of increased intracranial pressure (40%), personality disorders (15% to 20%), or focal neurologicaldeficits (10% to 15%) - Average duration of symptoms is 16months

Paraclinical examinations - Head Computed Tomography :hypodensesignificant oedima.Often the tumor boundaries are not definedContrast uptake at 80% to 90 of cases

- Magnetic resonance imaging (MRI) of the brain : Less clearly defined tumor boundariesof the low-grade astrocytomasModerate oedema.More inhomogeneous signal than in low-gradeastrocytomasContrast uptake variesMinimum hemosiderin

Treatment-Surgical removal

-Postoperative radiotherapy depends on the extent of tumor resection

-In case of recurrence reoperation, chemotherapy,brachytherapy and radiotherapy are recommended

Result

-2-year survival is around 40% to 50%

-5-year survival is around 18%after surgery and radiotherapyand chemotherapy

Prognostic factors are age, functional statusof the patient and theresidual tumor

45% of tumorsthat relapse are alreadyhigher grade glioma

HISTOLOGICAL PROFILE

•Moderate polycytosis•Moderate pleomorphism of cells andof nuclei•Local anaplastic changes•Necrosis points

4) GLIOBLASTOMA MULTIFORME (GBM)

Average age: 50-60 years

Percentage: 45% to 50% of gliomas

Localization:- Cerebral hemispheres mainly (40% in the frontal lobe, 25% in the temporal lobe and 25% in the parietal lobe) - Sometimes in the corpus callosum (butterfly glioma)- In the strain less often

Clinical profile

- Epileptic attacks constitute 32%

- Symptoms of increased intracranial pressure (86% headache, 45% nausea and vomiting

-Personality Disorders (47%) and motordeficits (44%), also often symptoms

Paraclinical examinations

- Head Computed Tomography :Heterogeneous hyperintense area highlights necroticareasSignificant oedima and displacement of midline structuresBlurred boundariesAt least 95% of these tumors take up contrastThere are instances that the tumor crosses the midline

- Magnetic resonance imaging (MRI) of the brain : The tumor boundaries cannot be determinedLarge oedema and displacement of midline structuresInhomogeneous signal inside the tumorContrast uptake is the same as that visualized in CTBleeding is often and so is the presence of haemosiderin

Treatment-Surgical removal

-Postoperative radiotherapy depends onthe extent of tumor resection

-In case of recurrence reoperation, chemotherapy, brachytherapy and radiotherapy are recommended

Result

- 2-year survival is around 10%- 5-year survival is around 5.5%-The average survival after surgery, surgery and radiation therapy, or surgeryand radiotherapy and chemotherapy is 4,9.25, and 10 months respectively-Reoperation and / or brachytherapy mayincrease survival by 9 to 12 monthsin some patients

Prognostic factors are age, functional statusof the patient and theresidual tumor aftersurgery and radiotherapy

Some neurosurgeons recommend only biopsy and adjuvanttherapy for high malignancysupratentorial tumors

HISTOLOGICAL PROFILE

•Polycytosis•Pleomorphism of cells andof cytoplasm•Often vascular hyperplasias•Necroses frequently

6) OLIGODENDROGLIOMA

Average age: 43 years

Percentage: 4% to 6% of gliomas

Localization:- Cerebral hemispheres (50%) in the frontal lobe, (15% to 25%) in the temporal lobe and in the parietal lobe- Occipital (5%) rarely

Clinical profile - Epileptic attacks constitute > 50%

- Headache at 30% to 78%

- personality disorders, visual disturbances, and focal deficits (in the absence of seizures)

Paraclinical examinations

- Head Computed Tomography : -Hypodense or isodense. - Areas with calcification seen in more than 70% of cases - Cystic areas and bleeding are rare - When there are anaplastic tumor elements calcification occurs less often - Oedema and contrast uptake are common only in anaplastic tumors

- Magnetic resonance imaging (MRI) of the brain : - Moderate or slight contrast uptake - Heterogeneous low frequency signal, due to calcination

Treatment

•Surgical removal•Radiotherapy after total resection•Some surgeons are not in favor of total resection of space lesion•They recommend chemotherapy and / or re-operation on residual tumor

Result

- Average survival is around 35 to 60 months5-year survival is around 35% to 60%10-year survival is around 25% to 30%-Radiotherapy prolongs life in averageby 12 months or less after subtotal tumor resection, but makes no difference when the patient has undergone total resection

Prognostic factors arefunctional status of the patient before thesurgery, the presence of calcification andlack of anaplastic elementsOver 50% of recurrent tumors mutate in anaplastic oligodendrogliomaLow-grade astrocytic elements do not aggravate the prognosisThe prognosis of mixed oligodendroglioma with anaplastic astrocytic elements is the same as in anaplastic glioma

HISTOLOGICAL PROFILE

•Homomorphic cells with oval nuclei,clear cytoplasm and defined cell membranes•Metallization at 70% to 90%•There may be suspicious astrocytic areas(Mixed oligodendroglioma)•There may be typical anaplasticchanges (anaplastic oligodendroglioma)

7) INTRACRANIAL EPENDYMOMA

Average age: 25 years

Percentage: 3% to 4% of gliomas

Localization:-4th cerebral ventricle. It may extend to cerebellopontine angle- In or near the third ventricle and the lateral ventricles-- 2/3 are located in the posterior fossa (most often in peopleof young age)1/3 is located in the supratentorial region (most often in adults)

Clinical profile

•Headache in more than 80% •Nausea and vomiting in 50% to 80%•Cerebellar disorders and oedema of the optic papilla•Average duration of symptoms is 4 months

Paraclinical examinations

- Head Computed Tomography :- Mixed density, isodense or slightly hyperintense-Areas with calcification appear in more than 50% of cases-There may be cystic areas, especially in cerebellar localization- More than 80% contrast uptake

- Magnetic resonance imaging (MRI) of the brain : - Punctated low intensity areas on T1-weighted sequencesdue to calcification or cystic sections of the tumor- Inhomogeneous gadolinium uptake

Treatment

•Surgical removal•Radiotherapy is of considerable importance.The dose depends on the location of the tumor,the malignancy grade and the surgical outcome•In case of tumor recurrence, reoperation and/orchemotherapy

Result

•5-year survival is around 35% to 60%

•1/3 to 2/3 will relapse if there areanaplastic elements

•Recurrences usually occur within 2years and more than 90% are localrecurrences

The rate of anaplasticchanges increases in supratentorial localizations

There is no clear correlation betweenanaplastic changes and the patient'soutcome

Rare or absent is the possibility thatthe recurrent ependymoma presentsanaplastic elements

HISTOLOGICAL PROFILE

Homomorphic ependymal cellsforming rosettes, orpseudorosettes around the vessels

FACTORS THAT DETERMINE THE SURGERY

Tumor factors

•The tumor as a space-occupying lesion•The localization (deep or superficial on vitalareas or not)•Its size•Its vascularization•Its composition (cystic or solid)•Its multiple localization

•Patient factors- The neurological condition- Age- Surgical risks (bleeding diathesis,inflammations)- Risks associated with anaesthesia(Respiratory, cardiological, metabolic)- Previous treatment- Family history and patient's history