Brain tumor/ Surgery

بسم الله الرحمن الرحيمBrain tumor

Brain tumours:Aetiology: viral infection Radiation & chemicals immunosuppression chromosomal abnormalities.

a. acoustic neuroma(NF2) to 22q. b. neurofibroma(NF1) to 17q. c. pituitary adenoma (MEN1) to 11q. d. haemangioblastoma(Von Hippel-Lindau) to 3p. e. meningioma to 22q. f. germ line mutation in the p53 tumour suppressor gene cause development of neumerous cancers including glioma, ependymoma, meningioma& medulloblastoma(the Li-Fraumeni syndrome).

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Gliomas: Astrocytomas:•Classification: WHO classified astrocytoma into:

Grade I = Pilocytic astrocytoma(hypercellularity). Grade II = Diffuse astrocytoma(hypercellularity,hyperchromatic nuclei,thickened vess).

GradeIII=Anaplastic astrocytoma(as above+mitosis, pleomorphism & vascular proliferation. Grade IV= Glioblastoma multiformi(as above + necrosis)

•The tumour is graded according to: •nuclear atypia, •mitosis, •endothelial proliferation,& •necrosis. •Where grade I have no features, grade II have one feature, grade III have 2 features & grade IV have 3 or 4 features.

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Investigation: Plain skull X-Ray:Brain CT scan: Brain MRI: Magnetic resonance spectroscopy (MRS) positron emission tomography (PET) & SPECT. Cerebral angiography:

Rx.: 1. Surgery. .2. RRx. 3. Adjuvant Rx.

Tumour biopsy stereotacticaly is indicated in: 1. Small deeply seated tumour. 2. Diffuse tumour without raised ICP. 3. Tumour involves highly eloquent area without ↑ ICP.

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•Oligodendroglioma: •5-15% of gliomas.•50% in frontal lobe, •Ca. deposition in90%.

•CF: raised ICP (in 1/3), FND(in 1/3) & epilepsy in about 80%. •Rad. Ix.: CT & MRI The tumour heterog. with enhancement & peritum oedema.

•Tt: 1. Surgery. 2. RRx. 3. Adjuvant therapy.

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Ependymoma:Arises from ependyma,5% of gliomas,2/3 infratentorialy,mostly in children, adolescents & young adults;1/3 supratentorialy& present in adults. CF.:↑ ICP d.to HC, cerebellar ataxia & S.&S. of brainstem compression.

Rad. Ix.: CT & MRI: vent. tumour of mixed density on CT & hypointense on T1WI MRI enhanced with contrast, calcification in 50% in tumour of lateral ventricle)+HC. Tt: surgery, Postoperative radiotherapy & whole neuraxis radiation to prevent CSF spread. The prx. depends on the grade of the tumor.

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Pineal tumour: classified in↓ frequency:

1.Germ cell tumours,(60%):a.Germinoma. b.Teratoma.c.Yolk sac(endod. sinus)tumour. d. Embryonal ca. e. Chorioca.

2.Pineal parenchymal tumours,(30%): a.Pineoblastoma.b.Pineocytoma.c.pineal parenchymal tumour of intermed.differentiation.

3.Tumours of suppo.cells & adj.structures, (10%):a.Glioma. b.Mnngma. c.Hgblastoma&Hpericytoma. d.Craniopharyngioma. e.Chemodectoma.

4.Non-neoplastic & metastatic tumours,(< 1%):a. Cysts(arachnoid/degenerative).b.AVM/V.ofG.M. c. Cysticercosis.d.Metastasis(lung,breast,stomach or kidney ca).

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CF:1. S.&S. of ↑↑ ICP. 2.FND. 3.Endocrine disturbances: Efferent cerebellar compression in sup. cerebellar peduncle →→ limb ataxia & q.geminal plate distorsion→→ upgaze & convergence paresis or retraction nystagmus + impairment of light & accommodation reflex.

Parinaud’s syndrome in 50-75% & convergence-retraction nystagmus on upgaze.

Direct pressure on tectum or dilatation of proximal aqueduct→Sylvian aqueduct syndrome (paresis of down gaze or horizontal gaze superimposed on Parinaud’s syndrome). Convergent nystagmus may be present. Endocrine disturb: precocious puberty & DI in 10%. d.to hypothalamus involvement or 2ry to HC.

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Investigation: CT scan, germinoma is hyperdense, with

contrast enhancement. Calcification is uncommon.

MRI, it is isointense on T1WI, slightly hyperintense on T2WI. it enhance homogeneously with gadolinium.

Normaly the pineal gland is calcified in 60% of population over the age of 20 years & very rarely in children before 6 years.

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Tumour markers: α-FP normaly ≤ 5 ng/ml in serum & CSF. yolk sac (endodermal sinus) tumour, embryonal ca &

immature teratoma produce α-FP to a lesser extent (<1000 ng/ml).

ß-HCG value in serum & CSF is < 5 mlU/ml. Chorioca

produce the highest amount of ß-HCG (>2000ng/ml. Mild elevation of < 770 ng/ml in cases of germinoma & embryonal ca.

Placental alk phosph. In 1ry intracranial germinoma. Melatonin is a tumour marker for tumours that destroy the

pineal gland. Elevation of polyamines putrescine & spermidine in the CSF

has been reported in malignant brain tumours of childhood specialy PNETs.

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Mx: 1.Sx. 2.RRx. 3.ChemoRx. 4.Nendoscopy. 5.Stereotactic procedures. V-P shunt or endoscopic 3rd v. for severe HC. RRx. (germinomas are radiosensitive). ChemoRx. Stereotactic biopsy. nendoscopy dx. tumors not amenable to sx. If serial CT show failure of RRx., or the initial CT & MRI are

atypical (not resemble germinoma), then sx is necessary.

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Metastatic tumours: 30-50% of brain tumours is metastasis. 20-40% of CA pt. develop brain metastasis. In ↓ order from: 1.Lung CA(40-60%). 2.Breast CA(15-20%). 3.Melanoma(10-20%). 4.Renal CA(5-10%). 5.GIT CA(5-10%).

In children, Wilm's, neuroblastoma & rhabdomyosarcoma are the most common primary.

In 15% of cases the primary origin is never found, 2/3 of cases are multiple & 1/3 are solitary, ½ of

these systemic spread is not apparent.

The incidence of tumours in cerebrum to cerebellum is 8:1 & mostly in the distribution of middle cerebral artery.

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CF.: 1. Raised ICP. 2. FND. 3. Epilepsy.

•Metastasis from melanoma or choriocarcinoma may present as stroke like attack from intratumoural hrg.

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Cerebral lymphoma

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CT or MRI show solitary or multiple metastasis isodense on native CT scan, enhance with contrast with surrounding cerebral oedema.

•Hyperdense metastasis on CT: melanoma, GIT adenoCA, chorioCA & 50% of lymphoma. •On MRI the lesion is hypo/isointense on T1WI surrounded by hypointense oedema & hyperintense on T2WI, hrgic tumor is hypointense on T2WI.

•Both melanotic melanoma & adenocarcinoma are hyperintense on T1WI & iso/hypo-intense on T2WI.

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In cases of unknown primary origin:

1. CXRay, mammography, urinalysis with blood count & biochemistry, skin survey.

2. CT scans of chest, abdomen & pelvis;

bone scan & stereotactic brain biopsy.

The 1ry origin remains undx in 15%.

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Tt: 1. Medical steroids & antiepileptics. 2. RRx. 3. ChemoRx. 4. Stereotactic radiosurgery. 5. Surgery.

Steroid 16mg/day after initial 10mg dexamethasone, with anticonvulsants for epileptic seizures.

Surgical resection is indicated in: a. Solitary metastasis in accessible position. b. Absence of systemic spread. c. Histopathological dx. d. Accessible lesion+significant mass effect&FND. Prx: secondaries from lung cancer & melanoma have 1 year

survival of 30% & from breast cancer is 50% after surgical resection.

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Paediatric Brain tumours: 40% supratentorium: astrocytoma & GBM, craniopharyngioma, PNET (medulloblastoma), ependymoma, ganglioglioma & pineal tumors.

60% in post fossa, include in ↓ order:Cerebellar astrocytoma 30%, Medulloblastoma 30%, Ependymoma 20%, Brainstem glioma 10%, Miscellaneous 10% & including: a.choroid plexus papilloma. b.haemangioblastoma. c.epidermoid & dermoid tumours. d.chordoma.

CF.: a.↑ICP. b.FND. c.increased OFC & HC.Ix.CT& MRI.Tt.:1.Surgery. 2. RRx. 3.ChemoRx.

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Brain CT (ependymoma).brain MRI brain stem glioma

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Meningiomas: 15% intracranial tumors, uncommon in children, frequent in women in 4th-6th decades of life, arises from the arachnoid. Parasagittal & falx = 25%, convexity = 20%, sphenoid wing = 20%, olfactory groove = 12%, supracellar = 12%, posterior fossa = 9%, ventricle=1.5%, optic sheath=0.5%.

Aetiology: Irradiation, chromosomal abn., sex hormones (female, breast cancer) & HI.

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•According to the WHO:1.Syncytial meningotheliomatous. 2.Transitional: 3.The fibroblastic4.Angiomatous5.Malignant/anaplastic. 6.Atypical. 7.Psammomatous. 8.Microcysti. 9. Secretory. 10. Lymphoplasmacyte-rich. 11. Metaplastic.12. Clear cell. 13. Chordoid.14. Rhabdoid. 15. Papillary meningioma.

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CF.: 1. ↑ICP. 2. FND. 3. Epilepsy. Ix.: CT scan hyperdense, enhanced. Hyperostosis/sclerosis & plain X-Ray.

On MRI isointense on T1WI, enhance homogenously, hyperintense on T2WI.

Angiography shows feeding vess. Tt.: preop. steroid & angiographic embolization of tumor vess. to↓vascularity. Craniotomy & total excision. RRx.: a. residual tumor. b. inoperable tumor. c. unresectable tumor. d. Recurrent tumor. e.malignant mnngioma & haemangiopericytoma. Stereotactic RRx./radiosx for small meningioma ≤ 3 cm not amenable to sx or elderly &/or medicaly unfit pt. steroid Rx. to minimize brain edema.

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Acoustic neuroma: Shwannoma from 8th cr.n.Microscopically: 2 pattern: Antoni A compact pattern, & Antoni B looser appearance. Bilateral acoustic neuromas are hallmark of NF.II which inherited as AD dz.

CF: Tinnitus, sensorineural deafness & vertigo. A tumor enlargement compress the 7th n.→ facial palsy, then 5th n. palsy with facial hyposthesia & loss of corneal reflux. Later on cerebellar & brainstem compression → ataxia & pyramidal tract signs with contralateral hemiparesis & obstructive HC. with raised ICP.

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Lisch nodules Bilateral acoustic neuroma

Neurofibroma

Periventricular calcification

Adenoma sebaceumTuberous sclerosis

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Dx.:Audiogram or pure tone audiometry. Brainstem auditory evoked responses:. Hallpike caloric test: impairment of vest. function. Brain CT shows round lobular isodense contrast enhancing CPA lesion with erosion of the IAC. Brain MRI shows isointense lesion on T1WI with strong homogenous enhancement & hyperintense on T2WI. DDx.: a.Meningioma. b.Epidermoid cyst. c. Metastatic. d. Exophytic brainstem glioma.

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Tt: Sx. For HC & ↑ICP., V-P shunt. Steroid prior to sx for large tumor. 3 approaches: a.suboccipital retrosigmoid craniectomy.b.Translabyrinthine approach. c.Middle cranial fossa approach. Stereotactic radiosx indicated for: Elderly, Medicaly unfit pt., Residual &/or recurrent tumour less than 3 cm. Stereotactic radiosurgery is done with Gamma Knife or linear accelerator.

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Haemangioblastoma:10% of posterior FT, From proliferation of endothelial cells & occurs in young adults. It may occur as a component of VHL dz, in 38% of cases includes multiple haemangioblastomas, retinal haemangioblastoma, renal tumour & pancreatic cyst & tubular adenoma of epididymis.

Cerebellar haemangioblastoma in 20% of pt. with retinal haemangioblastoma.

Pathology: it involves dura in 20% of cases, In VHL dz. the mutant gene is located on chromosome 3p.

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Ataxia-telangiectasia

Ataxia-telangiectasia Sturge-Weber syndrome

von Hippel-Lindau syndrome

Hemangioblastoma ofcervical spinal cord Telangiectasis

Hemangioma of upper eyelid

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Epidermoid&dermoid: found in arachnoid spaces, mostly in CPA, supracellar & parasellar regions. The lat.& 4th vent.& qgeminal cistern. Dermoid occur in post.fossa as midline lesion with dermal sinus.

Pathology: Dermoid contain dermal elements such as hair follicles, sebaceous, sweat glands, mature teeth & pseudocartilage.

CF.: according to site. Rad. Ix.: Brain CT & MRI hypodense lesion not enhance. The dermoid is hypodense even to CSF due to fat content. Brain MRI shows epidermoid as hypointense lesion on T1WI & hyperintense on T2WI. Dermoid appear hyperintense on T1WI. Tt: is complete surgical resection of the cyst.

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Epidermoid & colloid cyst of 3rd ventricle

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Pituitary adenoma: 8-10% of intracranial tumours.

Classification: Chromophobic adenoma:.Acidophilic adenoma(GH) & prolactin.Basophilic adenomaACTH.

a. Prolactin secreting ad.(40%). b. GH secreting ad.(20%). c. Null cell ad.(20%). d. ACTH secreting ad.(15%). e. Mixed prolactin&GH secreting ad.(5%). f. FSH/LH secreting ad.(1-2%). g. TSH secreting adenoma. h. Acidophil stem cell(no hormone,1-2%).

Pathology: tumor from ant. lobe (adenohypoph.). Adenoma of<10mm.is Microadenoma, tumor grows within sella & cause erosion & remodeling of sellar floor & post.clinoid processes is Macroadenoma.

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Hormonal assay Rad Ix.: Brain CT & MRI with contrast. Pituitary microadenoma are hypodense lesion.Macroadenoma enhanced & the lesion is seen with coronal view. Microadenoma is hypointense on T1WI, hyperintense on T2WI. Macroadenoma is isointense on T1WI, hyperintense on T2WI. Hemorrhage (pituitary apoplexy) is hyperintense on T1 & T2WI.

Plain skull X-Ray shows enlarged sella with thining & erosion or bulging of its contour. Angiography can exclude incidental aneurysm & show the position of internal carotid artery. MRA & MRV replace angiography.

VA &F

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DDx: a.Craniopharyngioma. b.Tuberculum sellae meningioma. c.Optic n. or hypothalamic glioma. d. Giant aneurysm. e. Rathkes cleft cysts. f. Suprasellar germinoma. g. Chordoma.

1. Operative: a. trans-sphenoidal. b. trans-cranial.2. Medical Rx. 3. RadioRx.

Sx Tt. for: a. large tumour compresing the visual pathways.

b. GH secreting tumour causing acromegaly. c. ACTH secreting tumour causing Cushing’s dz. d. Intoleration of bromocriptine medical therapy of certain cases of prolactinoma which are either micro- or macroadenoma confined to the sella.

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Craniopharyngioma: Arises from epithelial remnants of Rathke’s pouch & extend through suprasellar cistern to hypothalamus.

The majority are cystic with yellow fluid & cholesterol crystals.

There are 2 histological types: The adamantinous type, & Papillary type or adult craniopharyngioma.

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SIADH: a. ectopic ADH d.to oat cell ca.or TB. b. ↑ n.hypophyseal ADH d.to HI, SAH. & meningitis.c. drugs stimulating ADH release like chlorpropamide, carbamazepine & tricyclic antidepressant.d. pituitary surgery & pituitary apoplexy.

CF.: wt.gain, weakness, lethargy, mental confusion, if Na drop below 120 mEq/L, seizures & coma ultimately.

Lab Ix: Hyponatraemia, hypotonicity of plasma, hypertonicity of urine to plasma & urinary Na+ concentration ≥ 20 mEq/L.

Exclude adrenal, thyroid, renal or hepatic dysfunction & prior diuretic use.

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DI: impairment of renal water conservation.

Causes: a.sellar & parasellar tumors (cpharyngioma) large nonfunctional pit. adenomas, germinomas & metastatic tumors. b. pit. & hypothalamic sx. c. infiltrative dz. as hypothalamic sarcoidosis & histiocytosis X. d. HI. & rupture IC aneurysm. e. idiopathic causes.

CF: polyuria, thirst, polydipsia & nocturia. Urine volumes reach>15 l/day. If H2O is restricted, dehydration rapidly become severe & → altered mental status, fever, hypotension & death. 

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Lab Ix. urine osm. of < 300 mOsm/kg H2O with urine sp.gr≤ 1.005 & plasma osm. > 287 mOsm/kg H2O.

To confirm dx. water deprivation test.

In normal & pt. with psychogenic polyuria & polydipsia (compulsive H2O drinking), endogenous ADH concentrates urine & preserve plasma osm., thus urine osm. exceeds 500 mOsm/kg & plasma osm. remain < 300 mOsm/kg before ADH injection & urine osm. rises < 5% after ADH.

04/14/23

In pt with psychogenic polydipsia (compulsive H2O drinking), H2O deprivation is prolonged for urine osm. to plateau & urine osm. does not increase after ADH.

In pt. with central DI, urine osm. plateaus at

300-500 mOsm/kg, plasma osm. may exceed 300 mOsm/kg & urine osm. rises > 9% after ADH.

Pt. with nephrogenic DI (renal tubular insensitivity to ADH), rise of urine osm. with dehydration is limited & not ↑ after ADH.