GLIOMAS Are tumors of the CNS that arise from glial cells They constitute 45% to 55% of intracranial tumors They are the most common tumors of the CNS

WHO CLASSIFICATION OF NEUROEPITHELIAL TUMORS   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   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 1 Increased number of cells Essentially of normal cytology form Pilocytic astrocytoma falls into this category Grade 2 Increased number of cells, but most of the cells are astrocytes Hyperchromatic nuclei No mitoses or necroses Few fine vessels

Grade 3 Many cells appear as astrocytes Pleomorphism Few mitotic figures Necrosis frequently Partial endothelial proliferation in vessels Grade 4 Few normal astrocytes appear Pleomorphism prevails Many bizarre mitoses Necroses frequently Endothelial proliferation in vessels prevails

1) PILOCYTIC ASTROCYTOMA 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

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%), or focal 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 is homogeneous. Small oedema. By injecting gadolinium the image is the same as in the CT.

Treatment Surgical removal Postoperative radiotherapy is controversial. - 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 years but not more.

86% of astrocytomas that relapse are already anaplastic Prognostic factors are age, physical condition of the patient and the extent of surgical resection

HISTOLOGICAL PROFILE Moderate polycytosis The nuclei may appear large but without any significant pleomorphism 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 neurological deficits (10% to 15%) - Average duration of symptoms is 16 months

Paraclinical examinations - Head Computed Tomography : hypodense significant oedima. Often the tumor boundaries are not defined Contrast uptake at 80% to 90 of cases - Magnetic resonance imaging (MRI) of the brain : Less clearly defined tumor boundaries of the low-grade astrocytomas Moderate oedema. More inhomogeneous signal than in low-grade astrocytomas Contrast uptake varies Minimum 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% after surgery and radiotherapy and chemotherapy

Prognostic factors are age, functional status of the patient and the residual tumor 45% of tumors that relapse are already higher grade glioma

HISTOLOGICAL PROFILE Moderate polycytosis Moderate pleomorphism of cells and of 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 motor deficits (44%), also often symptoms

Paraclinical examinations - Head Computed Tomography : Heterogeneous hyperintense area highlights necrotic areas Significant oedima and displacement of midline structures Blurred boundaries At least 95% of these tumors take up contrast There are instances that the tumor crosses the midline - Magnetic resonance imaging (MRI) of the brain : The tumor boundaries cannot be determined Large oedema and displacement of midline structures Inhomogeneous signal inside the tumor Contrast uptake is the same as that visualized in CT Bleeding is often and so is the presence of haemosiderin

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 10% The average survival after surgery, surgery and radiation therapy, or surgery and radiotherapy and chemotherapy is 4, 9.25, and 10 months respectively Reoperation and / or brachytherapy may increase survival by 9 to 12 months in some patients

Prognostic factors are age, functional status of the patient and the residual tumor after surgery and radiotherapy Some neurosurgeons recommend only biopsy and adjuvant therapy for high malignancy supratentorial tumors

Pleomorphism of cells and of cytoplasm Often vascular hyperplasias HISTOLOGICAL PROFILE Polycytosis Pleomorphism of cells and of 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 months 5-year survival is around 35% to 60% 10-year survival is around 25% to 30% Radiotherapy prolongs life in average by 12 months or less after subtotal tumor resection, but makes no difference when the patient has undergone total resection

Prognostic factors are functional status of the patient before the surgery, the presence of calcification and lack of anaplastic elements Over 50% of recurrent tumors mutate in anaplastic oligodendroglioma Low-grade astrocytic elements do not aggravate the prognosis The 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 anaplastic changes (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 people of 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 sequences due 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/or chemotherapy

Result 5-year survival is around 35% to 60% 1/3 to 2/3 will relapse if there are anaplastic elements Recurrences usually occur within 2 years and more than 90% are local recurrences

The rate of anaplastic changes increases in supratentorial localizations There is no clear correlation between anaplastic changes and the patient's outcome Rare or absent is the possibility that the recurrent ependymoma presents anaplastic elements

HISTOLOGICAL PROFILE Homomorphic ependymal cells forming rosettes, or pseudorosettes around the vessels

FACTORS THAT DETERMINE THE SURGERY Tumor factors The tumor as a space-occupying lesion The localization (deep or superficial on vital areas 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