What Are Brain Tumors Functioning

In This Article You Will Discover What Are Brain Tumors Functioning Brain Tumors can be Classified into either benign brain tumors or malignant brain tumors, almost all brain tumors are malignant in the sense that they may lead eventually to death if not treated. Brain tumors are responsible for 2% of all cancer deaths. The annual incidence of newly diagnosed brain tumors in the USA is approximately 18per 100000 persons,of which 30% are primary. In children, tumors of the CNS constitute 20% of all childhood malignancies.There is a peak at 2 years followed by a decline for the rest of the first decade.The incidence then slowly increases, peaking at 20 per 100000 in late adulthood.
 What Are Brain Tumors Functioning
The classification of brain tumors or types of brain tumours is determined by their cell of origin. Over 50% are neuroepithelial in origin, 15% metastatic, 15% meningiomas and 8% pituitary tumors. The World Health Organization WHO classification of brain tumors is

Pituitary tumors
Neuroepithelial tumors
Germ cell tumours as
Gliaomas as
1- Germinoma
1- Astrocytomas
2- Teraroma
2- Oligodendrogliomas
3- Epondymoma
Tumour like malformation as
4- Choroid plexus tumor
1- Cranipharyngioma
Pineal tumors
2- Epidermoid tumor
Neuronal tumours as
3- Dermoid tumours
1- Ganglioma
4- Colloid cyst
2- Gangliocytoma
Metastatic tumors
3- Neuroblastoma
Contiguous extension from regional tumors as
Glomus tumor
Nerve sheath tumor as

Acoustic neuroma

Meningeal tumors as

These brain tumors cause mass effect, dysfunc­tion or destruction of adjacent neural structures, swelling, abnormal electrical activity, or a combination of these.
Supratentorial tumors commonly present with focal neurologic deficit, such as contralat­eral limb weakness or visual field deficit, or headache or seizure. infratentorial tumors often cause increased ICP, due to hydrocephalus due to compression of the fourth ventricle, leading to headache. nausea, vomiting, or diplopia. Cerebellar hemisphere or brain stem dysfunction can lead to ataxia, nystagmus, or cranial nerve palsies. lnfratentorial tumors rarely cause seizures. All patients with symptoms concerning for brain tumor should undergo MRI with and without gadolinium, Initial management of a patient with asymptomatic brain tumor generally includes dexam­ethasone (if edema is present) and phenytoin (supratentorial tumors only). Patients with significant weakness, lethargy, or hydrocephalus should be admitted for observation until definitive care is adminis­tered
What Are Brain Tumors Functioning
Aetiology or Causes of brain tumors
The aetiology of brain tumors is still not clearly understood. Although there is no genetic predisposition, chromosome abnor­malities have been noted in many CNS tumours (e.g. von Recklinghausen's). Some chemicals show carcinogenic activity in animals, producing CNS tumors. Immunosuppression can markedly increase the incidence of primary CNS lymphoma. The current molecular understanding of oncogenesis involves both the addition of oncogenes to the genome and the loss of normally occurring tumor-suppressor genes. Mutation in the p53 tumor­ suppressor gene is the most common gene alteration and is found in both astrocytomas and meningiomas
 What Are Brain Tumors Functioning
What Are Brain Tumors Clinical features?
The clinical presentation of intracranial neoplasms or brain tumors will be as a result of one or a combination of raised intracranial prssure ICP, focal neurological signs, organic mental changes and seizures.
The ability of the intracranial contents to adapt an increase in volume is limited, and ultimately an increase in pressure will occur.
This will manifest itself initially as headache due to stretching. of the dura and blood vessels. In the initial phase, this headache is characteristically worse first thing In the morning and
progressive. Nausea and vomiting may be associated. vision might be disturbed due to papilloedema. Finally, a deterioration will occur in the level of consciousness as a serious and late conse­quence of raised ICP
What Are Brain Tumors Functioning
Late-onset epilepsy, particularly over the age of 30 years, should prompt investigations to exclude an intracranial neoplasm 40% of patients with supratentorial glial tumours will have expe­rienced a seizure by the time they come to surgery. Benign tumours may also be an underlying cause of long-standing epilepsy and may render the seizures surgically remediable. Focal neurological signs associated with intracranial neoplasms are related to the area of cortex involved. Contralateral sign are associated with lesions in the posterior frontal area (motor) or anterior parietal sensory lobe.
What Are Brain Tumors Functioning
 BrainTumours in the dommant hemisphere may cause problems with language (aphasia) and in the non-dominant hemisphere apraxia. The optic pathway may be involved, producing various visual symptoms, usually a contralateral homonymous hemi­anopia. Temporal lobe lesions frequently cause focal seizures with auras and visual field defects.
BrainTumors in the frontal lobes can grow to considerable sizes before producing altered cognitive func­tioning and subtle personality changes. Subfrontal lesions may involve the olfactory nerves (anosmia). Sellar and parasellar tumors present with visual field and acuity problems due to compression of the optic chiasma, hypopituitarism and over secre­tion syndromes such as Cushing's disease and acromegaly.
Brain Tumors in relation to the ventricular system may obstruct CSF drainage and result in hydrocephalus, compounding raised ICP. Tumours of the brain stem and cerebellopontine angle may result in cranial nerve palsies, long tract signs and secondary hydro­cephalus. Tumors involving the cerebellar vermis cause truncal ataxia, whereas tumours in the hemispheres produce appendicular signs such as incoordination and nystagmus
What Are Brain Tumors Functioning
Metastatic Brain Tumors
Metastatic Brain tumors constitute 15% of intracranial tumors Approximately 30% of deaths are due to cancer. and up to 25% of these have intracranial metastatic deposits at autopsy. 15% of cases, a primary source is never found. Up to 60% are multiple. with 85% situated above the tentorium. The interval between diagnosis of a primary and cerebral metastases varies considerably. Melanoma and renal carcinoma may present with haemorrhage.
What Are Brain Tumors Functioning
Metastatic brain tumors appear isodense on unenhanced CT but enhance vividly after intravenous contrast. Melanoma may appear hyperdense prior to contrast. MRI will frequently reveal lesions not visible on CT. A chest radiograph is essential to exclude a source or other metastatic deposits and to help grade the extent of disease.
 Steroids should be commenced to reduce peritumour oedema in order to reduce mass effect. Prolonged cancer patient survival and improved CNS imaging have increased the likelihood of diagnosing cerebral metastases.
The sources of most cerebral metastases are (in decreasing frequency) lie lung20%, breast20%, kidney11%, GI tract8%, and melanoma11% and unkown 15%. Lung and breast cancers account for more than half of cerebral metastases. Metastatic cells usually travel to the brain hematogenously through blood root and frequently seed.
What Are Brain Tumors Functioning
the gray-white junction. Other common locations are the cerebel­um and the meninges. The latter leads to carcinomatous meningitis is known as leptomeningeal carcinomatosis. MRl pre- and post­contrast administration is the study of choice for evaluation . Metastases are often very well circumscribed, round, and multiple. Such findings should instigate a metastatic work-up, including CT scan of the chest, abdomen, and pelvis, and a bone scan
What Are Brain Tumors Functioning
Treatment of Metastatic Brain Tumors
 Treatment of Metastatic Brain Tumors Depends on the primary tumor, tumor burden, patients­ medical condition, and location and number of metastases. The patient's and family's beliefs regarding aggressive care must be considered. Craniotomy may benefit patients with one or two ac­cessible metastases and should be discussed. Studies do not support craniotomy unless all detectable metastases can be resected. Surgery should be followed by whole brain radiation therapy. Surgery plus radiation therapy increases average survival from 1 month to 8 months
 Recent data suggest stereotactic radiosurgery (gamma knife) may be applied to multiple metastases in one session with improved outcome
What Are Brain Tumors Functioning
Glial Brain Tumors
Gliomas account for 50% of adult intracranial tumours and are usually supratentorial . They are of neuroectodermal origin arising from glial cells, of which there are four types: (1) astrocytes, (2) oligodendrocytes, (3) ependymal cells and (4) neu­roglial precursors. The most frequent is the astrocytoma. They rarely metastasis (except for medulloblastoma and ependy­moma) and spread along axonal pathways.Grading is on the basis of histological features, namely the presence of mitoses,necrosis, endothelial proliferation and nuclear atypia. Patients with low­ grade tumours have long median survival, whereas high-grade tumours (glioblastoma multiforme) are associated with a 20% year survival.
What Are Brain Tumors Functioning
CT scanning before and after contrast is able to localize and confirm the diagnosis in the majority of cases. The enhancement is often irregular around a centre of low density,which may repre­sent necrosis. Calcification may be present. MRI is more accurate in defining low-grade lesions. Tissue definition and anatomical localisation of lesions in and adjacent to eloquent
areas are also superior
 What Are Brain Tumors Functioning
Facilitating surgical planning and resection The aim of treatment is to obtain a pathological diagnosis and grading and to debulk the tumour, both to alleviate symptoms of raised pressure and as a precursor to adjuvant treatments. This usually involves a combination of surgery and radiotherapy to achieve optimal recurrence-free survival rates but will depend on the size and location of the tumour, as well as the patient's clini­cal state and age. Patients are started on dexamethasone in order to diminish cerebral oedema prior to surgery.Spread along axons makes total resection impossible unless the lesion is low grade. small and polar
What Are Brain Tumors Functioning
Radiotherapy for glial brain tumors
 Is usually as an external beam(50-60 Gy fractionated over 30 days), stereotactic focal irradia­tion using a Gamma KnifeTN or linear accelerator or brachyher­apy (implantation of a radioactive source). Chemotherapy has little role for lesions other than oligodendrogliomas but temazo­lamide ha a role in 30% of cases and its role in elderly patients is currently undergoing evaluation
What Are Brain Tumors Functioning
Photodynamic therapy for glial brain tumors immuno­therapy and gene therapy have all undergone clinical trials to determine advantages over conventional therapy with disappoint­ing results. In view of the poor prognosis with high-grade lesions, conservative treatment is often appropriate for selected patients.
What Are Brain Tumors Functioning
Astrocytomas Brain Tumors
Astrocytoma Brain Tumors is the most common primary brain or CNS neoplasm. The term glioma is often used to refer to astrocytomas specifically, ex­cluding other glial tumors. Astrocytomas are graded from I to IV.
Grades I and II are referred to as low-grade astrocytoma, grade III as anaplastic astrocytoma, and grade IV as glioblastoma multiform (GBM). Prognosis varies significantly between grades I/II, III, and IV, but not between I and II Median survival is 8 years after di­agnosis with a low-grade tumor, 2 to 3 years with an anaplastic astrocytoma, and roughly 1 year with a GBM. GBMs account for almost two-thirds of all astrocytomas, anaplastic astrocytomas ac­count for two-thirds of the rest, and low-grade astrocytomas the remainder. demonstrated the typical appearance of a GB
 What Are Brain Tumors Functioning
The great majority of astrocytomas infiltrate adjacent brain.Juvenile pilocytic astrocytomas and pleomorphic xanthoastrocy­toma are exceptions. These are circumscribed, low grade, and as­sociated.with good prognosis. Histologic features associated with higher grade include hypercelluarity, nuclear atypia, and endovas­cular hyperplasia. Necrosis is present only with GBMs: it is required for the diagnosis.
Gross total resection should be attempted for suspected astrocytomas. Motor cortex. language centers, deep or midline structures, or brain stem location may make this impossible without unacceptable, devastating neurologic deficit. These may require stereotactic needle biopsy. Gross total resection followed by radiation therapy improves survival for all grades, although radiation therapy may be delayed
What Are Brain Tumors Functioning
until recurrence in low-grade tumors. Chemotherapy may be consid­ered, but is of limited efficacy so far. There are various ongoing re­ search studies for GBM adjuvant therapy; these should be discussed with the patient and family. Other options are carmustine-containing wafers for local chemotherapy (Gliadel) and Iotrex-containing bal­loons for conformal radiation brachytherapy (Glia-Site), both placed in the resection cavity at the time of surgery. Adjuvant therapy re­ mains marginally effective; survival has changed little over the last several decades
What Are Brain Tumors Functioning
Oligodendroglioma Brain Tumors
Oligodendroglioma Brain Tumors accounts for approximately 10% of gliomas. They often present with seizures. Calcifications and hemorrhage on CT or MRI suggest the diagnosis. Oligodendrogliomas are also
What Are Brain Tumors Functioning
graded from I to IV; grade portends prognosis. Prognosis is better overall than for astrocytomas. Median survival ranges from 2 to7 years for highest and lowest grade tumors, respectively. Aggressive resection improves survival. Many oligodendrogliomas will respond to procarbazine, lomustine (CCNU). vincristine (PCV) chemother­apy. Radiation has not been clearly shown to prolong survival.
What Are Brain Tumors Functioning
Ependymoma Brain Tumors
The lining of the ventricular system consists of cuboidall columnar ependymal cells from which ependymomas may arise. Two-thirds of adult ependymomas are infratentorial, while most
What Are Brain Tumors Functioning
pediatric ependymomas brain tumors are supratentorial. Supratentorial ependy­momas arise from the lateral or third ventricles. The infratentorial tumors arise from the floor of the fourth ventricle (i.e off the back of the brain stem). The most common symptoms are headache, nausea, vomiting, or vertigo, secondary to increased ICP from obstruction of CSF flow through the fourth ventricle. The rumors may grow out the foramina of Luschka to form a cerebellopontine angle (CPA) mass. or may spread through the CSF to form "drop mets" in the spinal cord. Two main histologic subtypes are papillury ependymomas and anaplastic ependymomas. the latter characterized by increased mi­totic activity and areas of necrosis. Gross total resection is often impossible because the tumor arises from the brain stem. the goal of surgery is maximal resection without injuring the very delicate brain stem. Suboccipital craniotomy and midline separation of the cerebellar hemispheres allows access to tumors in the fourth ventri­cle. Postoperative radiation therapy significantly improves survival. Patients with CSF spread documented by lumbar puncture or con­ trast MRI should also have whole-spine radiation plus focused doses to visualized metastases.
What Are Brain Tumors Functioning
Choroid Plexus Papilloma Brain tuomrs
The choroid plexus Brain Tumors is composed of many small vascular tufts covered with cuboidal epithelium. It represents pan of the interface between blood and brain. The choroid cells create CSF from blood and release it into the ventricular system. Choroid plexus
and choroid plexus carcinomas (rare. mostly pediatric) may arise from these cells. Papillomas usually occur in infants (usually supra­ tentorial in the lateral ventricle). but also occur in adults (usually infratentorial in the fourth ventricle). Papillomas are well circum­scribed and vividly enhance due to extensive vasculature. Like ependymomas. adult choroid plexus papillomas usually present with symptoms of increased ICP. Treatment is surgical excision. Total surgical excision is curative; recurrent papillomas should be re-resected. Do not use radiation or chemotherapy for papillomas. Radiation is adjunctive to aggressive surgery for carcinomas. but results are poor regardless
What Are Brain Tumors Functioning
Neural Tumors and Mixed Tumors Brain Tumors
Neural and mixed tumors Brain tumors are a diverse group that include tumors variously containing normal or abnormal neuron and/or normal or abnormal glial cells. Primitive neuroectodermal tumors (PNET ) arise from bipotential cells. capable of differentiating Into neurons or glial cells.
Medulloblastoma Brain Tumors
PNETs are the most common medulloblastomas. Most occur in the first decade of life, but there is a second peak around age 30. Medulloblastoma is the most common malignant pediatric brain tu­mor. They are usually midline. Most occur in the cerebellum and present with symptoms of increased ICP. Histologic characteris­tics include densely packed small round cells with large nuclei and scant cytoplasm, They are generally not encapsulated. frequently disseminate within the CNS. and should undergo surgical resection followed by radiation therapy and chemotherapy
What Are Brain Tumors Functioning
Ganglioglioma Brain Tumors
Ganglioglioma is a mixed tumor in which both neurons and glial cells are neoplastic. They occur in the first three decades of life. often in the medial temporal lobe. as circumscribed masses that may contain cysts or calcium and may enhance. The presenting symptom is usually a seizure, due to the medial temporal location. Patients have a good prognosis after complete surgical resection.
What Are Brain Tumors Functioning
Neural Crest Tumors
Multipotent neural crest is develop into a variety of disparate cell types. including smooth muscle cells. sympathetic and parasym­pathetic neurons. melanceytes, Schwann cells. and arachnoid cap cells. They migrate in early development from the primitive neural tube throughout the body.
What Are Brain Tumors Functioning
Miscelianeous Brain Tumors
Meningioma Brain Tumors
These account for 15% of intracranial neoplasms and are the most common benign neoplasms. They are uncommon in chil­dren, occur more frequently in women than men, and their inci­dence peaks in middle age. They originate from meningothelial cells that occur in the greatest abundance in the arachnoid villi, correlating with their site of occurrence. They are most com­monly found along the superior sagittal sinus (parasagirtal), over the free convexity and falx, along the sphenoid wing, beneath the frontal lobes (olfactory groove and tuberculum sellae), within the posterior fossa (cerebellopontine angle and foramen magnum), in the optic nerve and in the ventricles. They classi­cally arise from a broad base along the dura, may invade bone, and derive their blood supply from the external carotid circula­tion
What Are Brain Tumors Functioning
There is a spectrum of histological appearances but malignant meningiomas are relatively rare. Surgical treatment should be, wherever possible, total excision. If this includes the site of dural attachment, the recurrence rate is less than 10%. Incomplete excision of the dural attachment will result in a recurrence rate of between 20% and 30%. Subtotal excision will result in 40% show­ing progressive growth. The role of radiotherapy is controversial and is usually reserved for tumours with aggressive histological features or recurrent rumours, when a subtotal resection has been performed. It is also used for cavernous sinus tumours
What Are Brain Tumors Functioning
Meningiomas are derived from arachnoid cap cells of the arachnoid mater. They appear to arise from the dura mater grossly and on MRl. and so are commonly referred to as dural-based tu­mors. The most common intracranial locations are along the falx the convexities (i.e. over the cerebral hemispheres). and the sphenoid wing. Less common locations include magnum, olfactory groove, and inside the lateral ventricle. Most are slow growing, encapsulated, benign tumors. Aggressive atyp­ical or malignant meningiomas may invade adjacent bone or into the cortex. Previous cranial irradiation increases the incidence of meningiomas. Approximately 10% of patients with a meningioma have multiple meningiomas. Total resection is curative, although involvement with small perforating arteries or cranial nerves may make total resection of skull base tumors impossible without signif­icant neurologic deficit. Small, asymptomatic meningiomas can be followed until symptomatic or significant growth is documented on serial imaging studies. Atypical and malignant meningiomas may require postoperative radiation. Patients may develop recurrences from the surgical bed or distant de novo tumors.
What Are Brain Tumors Functioning
Vestibular$chwannoma or Nerve Sheath Brain tumours
 (AcousticNeuroma)Vestibular schwannomas these are benign tumours arise from schwann cells and have a predilection for sensory nerve especially arise from the superior half of the vestibular portion of the vestibulocochlear nerve eighth nerve (cranial nerve VIIl) and less frequently by the fifth nerve schwannomas of the eighth nerve arise from the superoir or inferior vesibular portion in the internal auditory canal as the tumour grows it expands the internal auditory canal and extends into the cerbellopontine angle compressing the pons cerbellum and cranial nerves They most 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. NF-2 patients have an increased incidence of spinal and cranial meningiomas and gliomas.
What Are Brain Tumors Functioning
Vestibular schwannomas may be treated with microsurgical re­section or with conformal stereotactic radiosurgery (gamma or linear accelerator technology). The main complication with treat­ment is damage to the facial nerve (cranial nerve VII, which runs through the internal auditory canal with the vestibulocochlear nerve. Risk of facial nerve dysfunction increases with increasing tumor diameter
What Are Brain Tumors Functioning
Pituitary Tumors
Classification of Pituitary tumours

Endocrine active
Clinical syndrome
Secretory product
Acromegaly gigantism
Growth hormone GH 20%
Cushing,s disease
Adrenocorticotrophic hormone ACTH 15%
Amenorrhoea galactorrhoea impotence
Prolactin PRL 40%
Thyroid stimulating hormone TSH 1%
Behaves as endocrine inactive
Follicle stimulating hormone FSH Luteinising hormone LH  1-2%
Alpha subunit 20%
Endocrine inactive
What Are Brain Tumors Functioning
Pituitary tumours account for 8% of all intracranial rumours. Historically, they were classified according to their staining characteristics seen on light microscopy. However, the three types (chromophobe, acidophilic and basophilic) did not corre­spond closely with the clinical syndromes of pituitary hyper­secretion. The subsequent development of immunological staining techniques and electron mcroscopy provided a more refined classification of pituitary tumors. It is now correct to classify pituitary tumors according to their size [micro­adenomas < 10 mm), mesoadenomas (10-20 mm) and macro­adenomas (> 20 mm) and whether they are endocrine active or inactive . These features will also determine their presentation.
What Are Brain Tumors Functioning
Clinical Features Of Pituitary Tumors
Pituitary tumours arise In the sella turcica and can expand up into the suprasellar cisterns, compressing the optic chiasm above and resulting In visual failure (cl~sslCally a bitemporal hemianopia
Careful assessment of the visual fields, visual acuity and optic fundi is therefore essential. They may also Invade laterally into the cavernous sinuses on each side, compressing the third to sixth cranial nerves.
What Are Brain Tumors Functioning
Endocrine disturbance is due to either hypopituitarism or excess secretion of a particular pituitary hormone. Prolactin­ secreting tumours are usually found in younger women and cause loss of libido, infertility, amenorrhoea and galactorrhoea. Corticotrophin-producing tumours cause Cushing's disease owing to cortisol excess. The principal features are moon face.abdominal striae, buffalo hump, hypertension and diabetes mellitus.
What Are Brain Tumors Functioning
Acromegaly is due to an overproduction of growth hormone.
What Are Brain Tumors Functioning
The disease is disfiguring, causing prognathism and overgrowth of Include hypertension, cardomyopathy, diabetes mellitus, exces­sive sweating, arthralgias and lassitude. Haemorrhage Into a macroadenoma, known as pituitary apoplexy, can precipitate an acute presentation with headache, hypopituitarism and visual failure. Diabetes Insipidus, a product of direct hypothalamic involvement, is usually indicative of a craninopharyngioma or metastatic lesion and is rarely caused by pituitary adenomas.
What Are Brain Tumors Functioning
Investigations Of Pituitary Tumors
Diagnosis is confirmed by laboratory assessment of pituitary endocrine function, neuroradiological Imaging and formal visual assessment.Radioimmunoassay will identify the hormone being secreted. It is important, particularly with acute presentations, to exclude a prolactinoma as (he majority of these will respond rapidly to treatment with the dopamine agonist bromocriptine. Prolactin levels above 200 ng ml are usually diagnostic. Non-functiomng macroadenomas may cause hyperprolactinaemia due to distor­tion of the pituitary stalk or impingement on the hypothalamus.
What Are Brain Tumors Functioning
This is because the latter produces prolactm-inhibiting factor, which, under normal circumstances, suppresses prolactin levels to below 15 ng ml . Diagnosis of Cushing's disease is made by radioimmunoassay of adrenocorticotrophic hormone (ACTH) in the peripheral blood and petrosal venous sinus sampling to detect a brain-peripheral concentration gradient
With the exception of some patients with Cushing's disease MRI of the sella will confrim diagnosis of an intrasellar mass the resolution of MRI will also detect all but the smallest less than 2 mm tumours and any extrasellar extension
What Are Brain Tumors Functioning
Treatment Of Pituitary Tumors
Treatment of pituitary tumors depends on the endocrine disturbance present and the effect of compression of adjacent neural structures. For pro­llactinomas, dopamine agonist therapy should be commenced.
Surgical excision is reserved for macroadenomas compressing the optic chiasm, growth hormone-secreting tumours causing acromegaly and ACTH-secreting tumours causing Cushing's disease  Occasionally surgery is undertaken in patients with prolactinomas who are not responding to medical treatment
 or when unwanted side-effects occur. This is usually performed via a trans-sphenoidal route, although the Transcra­nial route can be used. The aim is to preserve normal pituitary function if possible. Surgery should be covered with parenteral hydrocortisone, and frequently vasopressin is required
What Are Brain Tumors Functioning
Radiotherapy is used for subtotal resections and for persistent hypersecretion of pituitary hormones. The long-term follow-up of non-functioning pituitary adenomas has shown a recurrence rate approaching 40% at 10 years, indicating that there is perhaps a more extensive role for this modality and that postoperative patients should be more closely followed up.
What Are Brain Tumors Functioning
Pituitary ademomas arise from the anterior pituitary gland (the adenohypophysis). Tumors less than 1cm diameter are microade­nomas; larger tumors are macroadenomas. Pituitary tumors maybe functional (i.e., secrete endocrinologically active compounds at pathologic levels) or nonfunctional (i.e., secrete nothing or in­active compounds). Functional tumors are often diagnosed when quite small, due to endocrine dysfunction. 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.
What Are Brain Tumors Functioning
Nonfunctional tumors commonly present when larger due to mass effect. Com­mon symptoms include visual field deficits due to compression of the optic chiasm, or panhypopituitarism due to compression of the gland. Hemorrhage into a pituitary tumor causes abrupt symptoms of headache, visual disturbance, decreased mental status, and en­docrine dysfunction. This is known as pituitary apoplexy. Pituitary tumors should be decompressed surgically to eliminate symptomatic mass effect and or to attempt endocrine cure. Prolactinomas usually shrink with dopaminergic therapy. Consider surgery for prolactinomas with persistent mass effect or endocrinologic dysfunction inspite of adequate dopamine agonist therapy, Most pituitary tumors are approached through the nose by the trans sphenoidal approach. Endoscopic sinus surgery techniques may be helpful and are in and increasingly being used­
What Are Brain Tumors Functioning
Hemangioblastoma Brain Tumors

Hemangioblastomas brain tumors occur almost exclusively in the posterior fossa. Twenty percent occur in patients with von Hippel-Lindau (VHL) disease, a multisystem neoplastic disorder. Other tumors as­sociated with VHL are renal cell carcinoma, pheochromocytoma, and retinal angiomas. Many appear 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. Pathology reveals abundant thin-walled vascular channels, so inter­nal debulking may be bloody. Enbloc resection of the mural nodule alone, leaving the cyst wall, is sufficient.
 What Are Brain Tumors Functioning
Lymphoma Brain Tumors
CNS lymphoma may arise primarily in the CNS or secondary to systemic disease. Recent increasing incidence may be due to increasing numbers of immunocompromised people in the transplant and AlDS populations. Presenting symptoms includi-mental status changes, headache due to increased lCP, and cranial nerve palsy due to lymphomatous meningitis (analogous to carcinomatous meningi­tis). Many are hyperdense on CT scan due to their dense cellularity, and most enhance. Surgical excision has little role. Diagnosis is often made by stereotactic needle biopsy. Subsequent treatment in­cludes steroids, whole brain radiation, and chemotherapy. Intrathe­cal methotrexate chemotherapy is an option.
 What Are Brain Tumors Functioning
Embryologic Tumors Of The Brain
Embryologic tumors result from embryonal remnants that fail to involute completely or differentiate properly during development
What Are Brain Tumors Functioning
Craniopharyngioma Of The Brain
Craniopharyngiomas are benign cystic lesions that occur most frequently in children. There is a second peak of occurrence around 50 years of age. All pediatric, and half of adult craniopharyngiomas calcify. Symptoms result from compression of adjacent structures, especially the optic chiasm. Pituitary or hypothalamic dysfunction or hydrocephalus may develop. Treatment is primarily surgical. Ex­cision is easier in children, as the tumor is usually soft and suckable. Adult tumors are often firm and adherent to adjacent vital structures. Visual loss, pituitary endocrine hypofunction, diabetes insipidus, and cognitive impairment from basal frontal injury may result from incautious resection
What Are Brain Tumors Functioning
Epidermoid tumours Of The Brain
These are cystic lesions with stratified squamous epithelial cells from trapped ectodermal cell rests that grow slowly and linearly by desquamation into the cyst cavity. The cysts contain keratin, choles­terol, and cellular debris They occur most frequently in the cerebellopontine angle and may cause symptoms due to brain stem compression. Recurrent bouts of aseptic meningitis may oc­cur due to release of irritating cyst contents into the subarachnoid space (Mollaret's meningitis). Treatment is surgical drainage and removal of cyst wall. Intraoperative spillage of cyst contents leads to severe chemical meningitis and must be avoided by containment and aspiration
What Are Brain Tumors Functioning
Dermoid tumors Of The Brain
Dermoids are less common than epidermoids. They contain hair follicles and sebaceous glands in addition to a squamous epithelium Dermoids are more commonly midline structures and are associated with other anomalies than are epidermoids. They may be traumatic, as from a lumbar puncture that drags skin structures into the CNS. Bacterial meningitis may occur when associated with a dermal si­nus tract to the skin. Treatment of symptomatic lesions is surgical resection. again with care to control cyst contents
What Are Brain Tumors Functioning
Teratoma Of The Brain
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Teratomas are germ cell tumors that arise in the midline, often in the pineal region (the area behind the third ventricle, above the midbrain and cerebellum). They contain elements from all three embryonal layers: ectoderm, mesoderm, and endoderm. Teratomas may contain skin, cartilage, GI glands, and teeth. Teratomas with more primitive features are more malignant, while those with more differentiated tissues are more benign. Surgical excision may be attempted. Prognosis for malignant teratoma is very poor. What Are Brain Tumors Functioning

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