extra-axial tumors
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#3. Recognize specific syndromes; extra-axial (cerebellopontine, pituitary, frontal) and intra-axial in brain tumor presentation. Extra-axial Tumors. Extrinsic to the brain - PowerPoint PPT PresentationTRANSCRIPT
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#3. Recognize specific syndromes; extra-axial (cerebellopontine, pituitary, frontal) and intra-axial in brain tumor presentation
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Extra-axial Tumors
• Extrinsic to the brain• include meningiomas, schwannomas,
neurofibromas, and pituitary tumors, craniopharyngiomas as well as mesenchymal tumors of the skull, spine, and dura mater
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Meningioma
• Derived from arachnoid cap cells of the arachnoid mater
• Appear to arise from the dura mater grossly and on MRI: “dural based tumors”
• Most common intracranial locations: along the falx cerebri , the convexities and the sphenoid wing.
• Less common locations: foramen magnum, olfactory groove, and inside the lateral ventricle
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Meningioma
• Mostly slow growing, encapsulated, and benign
• Malignant may invade adjacent bone or into the cortex
• Previous cranial irradiation: risk• Tx: Total resection, post op radiation (atypical
and malignant melanoma)
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Postcontrast T1-weighted coronal MRI demonstrating a brightly enhancing lesion arising from the falx cerebri with moderate edema and mass effect on the right lateral ventricle. This is a falcine meningioma. Note also the small separate meningioma arising from the dura over the cerebral convexity.
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Vestibular Schwannoma (Acoustic Neuroma)
• Arise from the superior half of the vestibular portion of the vestibulocochlear nerve (CN VIII)
• commonly present with progressive hearing loss, tinnitus, or balance difficulty
• Large tumors may cause brain stem compression and obstructive hydrocephalus
• Bilateral acoustic neuromas are pathognomonic for neurofibromatosis type 2, a syndrome resulting from chromosome 22 mutation.
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Vestibular Schwannoma (Acoustic Neuroma)
• Tx: microsurgical resection or with conformal stereotactic radiosurgery (gamma knife or linear accelerator technology)
• Complication: damage to the facial nerve (cranial nerve VII)
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A. Postcontrast T1-weighted axial MRI demonstrating a brightly enhancing mass on the right vestibular nerve with an enhancing tail going into the internal auditory canal (arrowhead). Pathology demonstrated vestibular schwannoma
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Pituitary Adenoma• arise from the anterior pituitary gland (the
adenohypophysis). • Microadenoma: <1cm; Macroadenoma >1 cm• Functional (i.e., secrete endocrinologically active
compounds at pathologic levels) or nonfunctional (i.e., secrete nothing or inactive compounds).
• The most common endocrine syndromes are Cushing's disease due to adrenocorticotropic hormone (ACTH) secretion, Forbes-Albright syndrome due to prolactin secretion, and acromegaly due to growth hormone secretion.
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Pituitary Adenoma
• Nonfunctional tumors commonly present when larger due to mass effect.
• Common symptoms : visual field deficits due to compression of the optic chiasm, or panhypopituitarism due to compression of the gland.
• Tx: Surgery (Transphenoidal), medical (Prolactinomas)
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Postcontrast T1-weighted sagittal MRI demonstrating a large sellar/suprasellar lesion involving the third ventricle superiorly, and abutting the midbrain and pons posteriorly. The patient presented with progressive visual field and acuity loss. Pathology and lab work revealed a nonfunctioning pituitary adenoma.
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Hemangioblastoma
• occur almost exclusively in the posterior fossa.• Twenty percent occur in patients with von
Hippel-Lindau (VHL) disease, a multisystem neoplastic disorder
• Appears as cystic tumors with an enhancing tumor on the cyst wall known as the mural nodule.
• Surgical resection is curative for sporadic (non-VHL associated) tumors.
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Craniopharyngioma
• Benign cystic lesions that occur most frequently in children.
• Second peak of occurrence around 50 years of age.• Symptoms result from compression of adjacent
structures, especially the optic chiasm, pituitary or hypothalamic dysfunction or hydrocephalus may develop.
• Treatment is primarily surgical• Complications: Visual loss, pituitary endocrine
hypofunction, diabetes insipidus, and cognitive impairment from basal frontal injury
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Neurofibroma• more fusiform and grow within the parent nerve,
rather than forming an encapsulated mass off the nerve, as with schwannomas.
• They are benign but not encapsulated.• They present similarly to schwannomas and the
two may be difficult to differentiate on imaging. • Patients with multiple neurofibromas likely have
neurofibromatosis type 1, also known as von Recklinghausen's neurofibromatosis.
• Resection for symptomatic lesions should be offered.
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Intra-axial Tumors
• Intrinsic to the brain
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• ASTROCYTOMA:- MOST COMMON PRIMARY INTRA-AXIAL
BRAIN TUMOR (low & high grade) - INVOLVE ALL LOBES WITH PREFERENTIAL TO FRONTAL & TEMPORAL LOBES
- GRADING BASED ON HISTOLOGY: hypercellularity pleomorphism vascular proliferation necrosis - DIAGNOSIS: CT, MRI, Angiography
- TREATMENT: Surgery, Radiation, Chemotheraphy or Combination
G L I O M A
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Pilocytic Astrocytoma
Grade I
Low Grade Astrocytoma
Grade II
Anaplastic Astrocytoma
Grade III
Glioblastoma Multiforme
Grade IV
Median Age 13 years 35-45 years 46 years 50-60 years
Incidence 2% of gliomas 5%-25% of gliomas
10%-30% of gliomas
45%-50% of gliomas
Location Cerebellum, Brain stem, Optic nerve, Cerebral hemisphere
Cerebral hemispheres (frontal 40%), pons thalamus, midbrain
Cerebral hemispheres, thalamus, midbrain, pons
Any region particularly cerebral hemispheres (frontal 40%)
Presentation Depending on site, inc. ICP, seizures, motor deficit
Seizures(65%), Incr.ICP, Mental status change, motor deficit
Seizures(50%), Incr.ICP,
Mental status change, motor deficit
Increased ICP, mental changes, motor deficit, seizures
Treatment Surgical resection
Surgical resection
Sx resection, radiaion, chemoRx
Sx resection, radiaion, chemoRx
Outcome
5 year survival
100% 26%-33% 18% 5.5%
ASTROCYTOMA
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OLIGODENDROGLIOMA
Incidence 2-10%
Age of predilection 30-55 yrs
Gender distribution Slightly more men (3:2)
Location Frontal, temporal, parietal often towards the midline
Cardinal clinical symptoms Seizures (50%-80%)
CT native Image as for astrocytma II or III, calcifications in about 50% of the cases, occasionally cysts, “fried egg” cytoplasm
CT after contrast medium Enhancement of Grade III tumors only; variegated picture, slight edema
Treatment: vary from conservative treatment of some patients with serial imaging studies and no intervention to aggressive multimodal treatment including surgical resection, radiotherapy, and chemotherapy
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EPENDYMOMA
(10%)
• glial tumors that arise from ependymal cells within the central nervous system
Incidence 1-4%
Age of predilection 0-20 yrs
Gender distribution Predominantly men
Location Fourth and third ventricles, lateral ventricles, in childhood frontal, superficial frontier
Cardinal clinical symptoms Signs of intracranial pressure increase
CT native Slightly increased density; calcification possible
CT after contrast medium Slightly enhancement in solid tumor parts; grades III and IV similar to glioblastoma image
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E P E N D Y M O M A
KEY FEATURES:-USUALLY OCCUR IN THE FLOOR OF THE 4TH VENTRICLE-POTENTIAL FOR SEEDING THRU THE NEURAXIS-WORSE PROGNOSIS THE YOUNGER THE PATIENT; 5 YRS SURVIVAL AT 80% FOR ADULTS & 20%-30% IN PEDIATRIC GROUP-MAXIMAL RESECTION FOLLOWED BY XRT