CNS tumors

Dr. Waleed Dabbas

Background

Frequency

Children : -Posterior fossa tumors ( Infra-Tentorial).

-Astrocytoma, Ependymoma, and Medulloblastoma.

Adults : -The most common malignant brain tumor in adults is GBM.

Incidence

• Overall incidence of primary brain tumor is 9.5 cases per 100,000 population in the United States.

• More than 50% are gliomas

• Brain tumors represent 30% of all childhood malignancies

Epidemiology

• Gender

– Slight increased brain tumors in males

– Two peaks

• Smaller peak in pediatric age group

• Second peak in elderly population between 70-80 years of age

Etiology and Risk Factors

• Several genetic disorders cause or increase risk for brain tumors.

– Neurofibromatosis

– Tuberous sclerosis

– Turcots syndrome

– Osler-Weber-Rendu syndrome

– Li-Fraumeni syndrome

Symptoms and signs

• Seizures – 54% at presentation

• Headaches – 71%

• Mental change – 53%

• Hemiparesis – 43%

• Cranial nerve – 14%

Brain tumor syndromes

• Seizure : Cortical lesion• Behavioral : Anterior Cranial fossa.• Weakness: internal capsule or primary motor cortex• Vision : optic nerve compression• Speech: Broca’s area.• Endocrine : prolactinoma , etc..• Torticollis : post. Cranial fossa tumor compressing the

XI nerve.• Anosmia : Foster-Kennedy Syndrome ( ant. Cranial

fossa tumor ) “ ipsilateral Optic nerve atrophy + Contralateral papilledema “

Diagnosis

• Imaging studies available are MRI– On MRI the high grade of malignant gliomas

appear as contrast enhancing mass lesions

• CT scan– Contrast enhanced CT scan for use if MRI is

unavailable

• Nuclear medicine studies– Brain scan not used much now

Classifications

By origin : Primary VS secondary

By location : supratentorial VS infratentorial

By cell type e.g. glioma,menengioma,oligodendroglioma>>>

By grade: 1,2,3,4

Benign VS malignant ?

Meningioma

Menengiomas

• Benign, Rarely malignanat

• Can grow at any part of the meninges, common sites: cerebral convexity, falx cerebri, parasagital.

• Age: 40-50 .

• More in Female “ progesterone receptors on meningiothelial cells” .

Hemangioblastoma

• Benign

• Most common adult Primary Post. Cranial Fossa tumor

• Highly Vascularized

• Two forms : Cystic VS. Solid.

Neuroepithelial TumorsGLIOMA

Type of Cells:

A. Astrocytic tumors

B. Oligodendroglial tumors

C. Ependymal tumors

D. Mixed gliomas

E. Choroid plexus tumors

Grade: Low VS. High

Location: SupraTentorial VS. InfraTent.

Astrocytoma

Grade I & II:- Superficial & Infratentorial. ( Benign )

- Young ages(Juv. Cerebellar Astrocytoma)

Grade III & IV: Anaplastic Astrocytoma

Glioblastoma Multiforme

Oligodendroglioma

• Microcalcification is common.

• Well differentiated VS Anaplastic “less common”

Ependymoma

• Ependymal cells that line the ventricles.– less than 2% of brain

tumors.– Usually low grade

histology but have a high grade of recurrence

• Supratentorial 3rd

ventricle+malignantInfratentorial 4th

ventricle+Benign“morecommon”

Choroid Plexus Papilloma* Rare *

• From the Choroid plexus inc.CSF production

Hydrocephalus.

• Supratentorial Children ( Lateral Vent. )

Infratentorial Adult ( Rare )

Medulloblastoma

• PNET (30% of pediatric brain tumors )

• Midline in the vermis of the cerebellum & extend to the 4th

ventricle.

• Young, hydroceph., ataxia.

• Spread through CNS, bone.

Pituitary tumors

Pituitary tumors have three features:

Local mass effect

Visual field disturbance (bitemporal hemianopia).

headache

Hormone deficiency: deficiency tend to first suppress LH and GH, followed in sequence by loss of TSH,ACTH and FSH

Hormone excess

Craniopharyngioma

Derived from remnants of the structures that give rise to pituitary gland.

Mass effect (headache, visual field defect)

Hormonal deficiencies

Could be cystic or solid with or without calcification.

Spinal tumors

1 Extradural :

Secondary deposits in the spine(commonest)

primary vertebral bony tumors(osteoclastoma,myeloma)

Lymphomas

2 Intradural extramedullary

Meningioma

Neurofibroma

3 Intramedullary (rare)

Glioma

Ependymoma

Others such as hemangioma

Involvement of the CNS by Systemic Cancer• Brain metastases occur in 25-35% of all cancers.

– The peak incidence of brain metastases is bimodal ages 0-10 years and age 55-59 years.

– Location• 50% of brain metastases are supratentorial

– Lung cancer and breast cancers are most common metastatic tumors to the head.

– Melanoma has greatest potential for metastasis to the brain.

– Approximately 40% of all patients with systemic disease develop brain metastases.

Prognostic Factors

• Include pathological grade, patient age and overall patient function at the time of diagnosis and duration of symptoms.

• Immediate survival with resection, radiotherapy and chemotherapy is three years for those with anaplastic astrocytoma and one year for those with glioblastoma multiform.

Treatment

• Includes supportive and definitive treatment

– Supportive agents are anticonvulsant and corticosteroids

– Definitive therapy for intracranial tumor is surgery

Treatment

• Surgical tools available include:

– Stereotactic frames• Definition provided three dimensional imaging system for accurate

targeting of brain lesions identifed on CT or MRI scan

– Image based guiding system• Definition frameless for image guided stereotactic system. Use

computer technology to co-register pre-operative imaging studies with intra-operative head position. These systems facilitate more complete tumor resection.

Radiation Therapy

• Radiation plays a central role in treatment of brain tumors in adults.

– Whole brain versus partial brain radiation

– Dose to the response of low grade gliomas

– Other alternatives to conventional radiotherapy include hyperfractionated radiotherapy or use of radiosensitizers and boron neutron capture therapy

Chemotherapy

• Chemotherapy regimens for gliomas include:

– Single agent BCN4 or combination chemotherapy of CCNU, procarbazine and vincristine