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Benign Brain Tumors

Henry Ford Hospital

Paul Mazaris PGY III

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Types of CNS tumors

• Tumors of neuroepithelial tissue• Tumors of cranial and spinal nerves• Tumors of the meninges• Hematopoietic neoplasms• Germ cell tumors• Cysts and tumor-like lesions• Tumors of the cellar region• Local extensions from regional tumors • Unclassified tumors

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Neuroepithelial tumors

• Astrocytic tumors• Oligodendroglial tumors• Ependymal tumors• Mixed gliomas• Choroid plexus tumors• Neuornal and mixed neuronal-glial tumors• Pineal tumors• Embryonal tumors

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1. Neuroepithelial tumors• Astrocytic tumors

– Astrocytoma (WHO grade II)– Anaplastic astrocytoma (WHO grade III)– Glioblastoma multiforme (WHO grade IV)– Pilocytic astrocytoma (WHO grade I)– Subependymal giant cell astrocytoma (WHO grade I)– Pleomorphic xanthoastrocytoma (WHO grade I)

• Oligodendroglial tumors– Oligodendroglioma (WHO grade II)

• Ependymal cell tumors – Ependymoma (WHO grade II) – Subependymoma (WHO grade I) – Anaplastic ependymoma (WHO grade III)

• Mixed gliomas – Mixed oligoastrocytoma (WHO grade II)

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• Tumors of the choroid plexus • Neuronal and mixed neuronal-glial tumors • Pineal Parenchyma Tumors • Tumors with neuroblastic or glioblastic elements (embryonal tumors)

2. Tumors of the Sellar Region

3. Germ Cell Tumors

4. Tumors of the Meninges– Variants – Atypical meningioma – Anaplastic (malignant) meningioma

5. Tumors of Cranial and Spinal Nerves– Schwannoma (neurinoma, neurilemoma) – Neurofibroma

– Peripheral nerve sheath tumors

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6. Local Extensions from Regional Tumors – Paraganglioma (chemodectoma) – Chordoma

7. Cysts and Tumor-like Lesions

8. Mesenchymal, non-meningothelial tumors– Lipoma

– Hemangioblastoma

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Pilocytic Astrocytoma

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Pilocytic Astrocytoma

• Location– Optic gliomas and hypothalamic gliomas– Cerebral hemisphere– Brainstem gliomas– Cerebellum

• Radiographic apperance– Well circumscribed– Enhance with contrast– Cystic component– Most often periventricular

• Pathology– Rosenthal fibers

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Pilocytic astrocytoma:Optic & hypothalamic region

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Pilocytic Astrocytoma:Third ventricular region

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Pilocytic Astrocytoma:Cerebral hemisphere

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Pilocytic Astrocytoma:Cerebellum & brainstem

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Pilocytic Astrocytoma

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Pilocytic Astrocytoma

• CT– Hypodense to

isodense– Enhances with

contrast

• MRI– T1- Hypo/isointense – T2- Hyperintense

with enhancement of solid tumors and mural nodules.

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Pilocytic Astrocytoma

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Pilocytic Astrocytoma

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Pilocytic Astrocytoma

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Meningiomas

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Meningiomas

• Key features– Incidence: 15-20% of primary intracranial tumors– Slow growing– Usually cured if completely removed– Common locations

• Parasagittal• Convexity

– Hyperostosis of adjacent bone– Calcification– Hormonal receptors– Rarely metastasize– Arachnoid cap cells (NOT DURA)– Monosomy 22

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Meningiomas

• Locations– Cranial (90%)

• Parasagittal 21%• Convexity 15%• Tuberculum sellae 13%• Sphenoid ridge 12%• Olfactory groove 10%• Falx 8%• Lateral ventricle 4%• Tentorial 3.5%• Middle fossa 3%

– Spinal (9%)– Ectopic (1%)– Multiple meningiomas (9% of cases)

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Meningiomas:Paraagittal and falx

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Meningiomas:Convexity

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Meningiomas:Sphenoid wing

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Meningioma classification

Classification system:1. Meningothelimatous (Syncytial)2. Fibrous (fibroblastic)3. Transitional

Variants may be associated with any of the above 3 subtypes:

– Microcytic -Psammomatous– Myxomatous -Xanthomatous– Lipomatous -Granular– Secretory -Chondroblastic– Osteoblastic -Melanotic

4. Angioblastic5. Atypical meningioma6. Malignant meningioma

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Meningiomas• CT

– Homogenous, densely enhancing mass– Dural tail– Non-contrast Hounsfield numbers of 60-70– Cerebral edema

• MRI– T1

• Isointense 60-65%• Hypointense 35-40% (compared to grey matter)

– T2• Isointense 50%• Hyperintense 35-40%• Hypointense 10-15% (compared to grey matter)

– Homogenous enhancement with contrast– MRA/MRV

• Angio– Characteristically have external carotid artery

feeders.– Provides information about blood supply and

patency of the adjacent sinuses.– Sunburst pattern on angiography- prominent

late arterial vascular blush.– Mother-in-law sign: Tumor blush.

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Meningioma

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Meningioma

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Meningioma

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Meningioma

• Histology– Basophilic psammoma bodies & whorls

• Immunochemistry– +Vimentin– +EMA

• Treatment– Surgery

• Preoperative embolization• Symptomatic vs asymptomatic

– XRT• Malignant• Recurrent• Vascular• Non-resectable

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Choroid plexus papilloma

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Choroid plexus papilloma

• Key features– Intraventricular lesion– < 1% of brain tumors– Peak age is <10 years

• One of the most frequent brain tumors before 2 years.

– 50% are located in the lateral ventricle (left atrium in children)

– 40% are located in the fourth ventricle (in adults)– 10% are located in the third ventricle – Rarely located in the CPA cistern

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Choroid plexus papilloma

• Features– Well circumscribed, vascular & enhancing– Benign – 25% have calcifications – Increased CSF protein & xanthrochromia are seen in

approximately 60% of cases.– Persistent hydrocephalus

• Presentation– Increased ICP from hydrocephalus

• HA, N/V, craniomegaly• Hemiparesis• CN deficits

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Choroid plexus papilloma

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Choroid plexus papilloma

• CT – Isodense to hyperdense

with prominent enhancement.

• MRI– Lobulated masses– T1: Isointense– T2: Isointense to slightly

hyperintense with enhancement

• Angiography– Prominent choroidal

feeders

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Choroid plexus papilloma

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Choroid plexus papilloma

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Choroid plexus papilloma

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Choroid plexus papilloma

• Histology – Cauliflower papillary

shaped appearance with cubodial and columnar cells.

– No nuclear atypia– Rare mitosis– No mucin

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Choroid plexus papilloma• Immunochemistry

– Transthyretin– Vimentin– Keratin– S100

• May rarely invade the underlying brain even with benign pathologic findings.

• May seed the CSF• Treatment

– Surgical resection– No role for chemotherapy

or radiation in benign lesions.

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Craniopharyngioma

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Craniopharyngioma

• Key fratures– Account for 2-5% of primary brain tumors– No sex predominance– Bimodal age distribution. Peak age 5-10 years with a

second peak between age 55-65.– 70% are suprasellar and intracellar– Arise form the anterior superior margin of the pitutary– Contain both solid and cystic components

• “Machine oil” fluid

– Do not undergo malignant transformation– Calcifications

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Craniopharyngioma

• Features– Symptoms– Benign- Intimate

adherence to the infundibular stalk and hypothalamus predisposes to a number of endocrinologic & neurobehavioral problems.

– Endocrinopathies in children

• Short stature

• Delayed puberty

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Craniopharyngioma

• Pathology– Adamantinomatous pattern

• Cholesterol clefts• Calcifications• Squamous cells

– Papillary pattern• Sheets of squamous epithelium• Keratin pearls

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Craniopharyngioma

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Craniopharyngioma

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Craniopharyngioma

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Craniopharyngioma

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Craniopharyngioma

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Craniopharyngioma

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Craniopharyngioma

• Preoperative evaluation– A complete endocrinologic evaluation is

performed before therapy.– Adequate thyroid replacement– Pre- and intraoperative replacement of

corticosteroids is mandatory and should be carried out radidly.

– A neuor-ophthalmologic evaluation is obtained to follow the patient’s postoperative and postradiation visual status.

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Craniopharyngioma

• Surgery– Tumor size– Degree of tumor adherence to the chiasm and great

vessels– Subtotal resection

• Biopsy and radiation• Stereotactic radiosurgery• Recurrent craniopharyngioma

– “Total” removal– Higher morbidity & lower probability of cure

• Predominantly cystic craniophayrngioma

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Central neurocytoma

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Central neurocytoma

• Features– Rare lesions – Affects young adults

• Males > females– Benign

• Malignant variation & behavior– Slow growing – Calcified– Location

• Septum pellucidum• Lateral ventricle• Third ventricle

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Central neurocytoma

• Variants:– Extraventricular neurocytomas– Central liponeurocytoma

• Pathology– Similar to oligodendrogliomas– Contain dense core vesicles

• Immunochemistry– Synaptophysin– Neuron-specific enolase

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Central neurocytoma

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Central neurocytoma

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Central neurocytoma

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Central neurocytoma

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Central neurocytoma

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Central neurocytoma

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Central neurocytoma

• Treatment– Surgery– Stereotactic radiosurgery– Chemotherapy

• Etoposide• Cisplatin• Cyclophosphamide

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