Glossary

A

Acoustic Schwannoma (Neuroma)

Schwannomas are benign tumors that arise from the nerve sheath (covering) of cranial nerves along-side the cerebellum and brainstem.

The optimal treatment for the majority of symptomatic schwannomas is maximal surgical removal or focused radiation (radiosurgery). Fortunately, for patients requiring schwannoma surgery, most large acoustic schwannomas can be removed through a retromastoid keyhole craniotomy while most trigeminal schwannomas can be removed through either a retromastoid approach or an endonasal endoscopic approach.  At the BTC, we have a large experience treating such skull base tumors with keyhole and endoscopic approaches.  By incorporating cutting edge technology and instrumentation with proven surgical experience, our schwannoma specialists make schwannoma surgery safer, less invasive and more effective.

Acromegaly

A pituitary hormonal disorder caused by a growth hormone (GH) secreting pituitary adenoma. The problems associated with acromegaly include the effects of GH and IGF-1 over-secretion, and in some instances by the tumor compressing the normal pituitary gland, and optic nerves. Untreated acromegaly is a serious condition that can cause dramatic bone and soft tissue changes including frontal bossing, prognathism, enlargement of the hands and feet, sleep apnea, and carpal tunnel syndrome. More serious problems can include cardiovascular disease, hypertension,diabetes mellitus and an increased risk of colon cancer. Primary treatment is endonasal transsphenoidal surgical removal.

Adenoma

A benign growth of cells arising from glandular tissue. All pituitary adenomas are benign although approximately 1 in 1000 tumor of pituitary gland origin are a pituitary carcinoma (malignant). Despite their benign histology, pituitary adenomas can still cause serious health conditions including hormonal loss (hypopituitarism), hormonal excess (acromegaly, Cushing’s disease, prolactinoma) visual loss and headaches.

Adrenal Glands

It is two paired triangular-shaped glands which sit atop the kidneys and consist of an outer adrenal cortex and an inner adrenal medulla. The adrenal cortex produces the stress hormone cortisol in response to the pituitary hormone ACTH (adreno-corticotropic hormone) and aldosterone which helps control water and sodium balance. The adrenal medulla produces the catecholamines epinephrine (adrenaline) and norepinephrine, both essential for the stress response and maintaining adequate blood pressure.

Adrenalectomy

It is surgical removal of the adrenal gland or glands. Bilateral adrenelectomy is used sometimes to treat persistent Cushing’s disease after failed or unsuccessful transsphenoidal surgery to remove the ACTH-secreting adenoma. One potential risk or bilateral adrenalectomy is the development of Nelson’s Syndrome – an aggressive ACTH-secreting pituitary adenoma.

Adrenocorticotropic Hormone (ACTH)

An essential pituitary hormone which causes the adrenal glands to release cortisol, the stress hormone. An ACTH-secreting pituitary adenoma is the cause of Cushing’s disease which is characterized by excess cortisol production. An ACTH deficiency may result in low cortisol levels and adrenal insufficiency which can be life threatening.

Amenorrhea

Absent or irregular menstrual periods in a woman of reproductive age. This condition can be caused by multiple conditions including problems with the ovaries, uterus, pituitary gland or hypothalamus. Hormonal disturbances from the pituitary gland and hypothalamus that can lead to amenorrhea include decreased luteinizing hormone (LH) and follicle stimulating hormone (FSH) production or excess prolactin production (hyperprolactinemia). These hormonal imbalances can result from pituitary tumors, brain tumors or other forms of damage to the pituitary gland such as radiation or head trauma. In women with a prolactinoma and high prolactin levels, amenorrhea is often associated with galactorrhea (abnormal breast milk production).

Aneurysm

A weakness on a wall of a blood vessel (artery) which may be congenital, developmental or traumatic in origin. Over time, the area of weakness may enlarge, balloon outward and eventually rupture. In the brain, a cerebral aneurysm rupture can cause abrupt severe symptoms of headache, stiff neck, nausea, photophopia and even coma or death. Unfortunately most aneurysms are not diagnosed until they rupture which leads to bleeding over the surface of the brain (subarachnoid hemorrhage) or into the brain itself. Urgent treatment of a ruptured cerebral aneurysm is indicated to prevent re-rupture which is typically fatal. Cerebral aneurysms are successfully treated by either clipping the aneurysm through a craniotomy or coiling the aneurysm through the artery itself using an endovascular technique. In recent years, endovascular treatment of aneursyms is becoming more safe and effective.

Arachnoid Cyst

It is cerebrospinal fluid filled cysts that arise from an abnormal development of the arachnoid membrane that covers the brain surface. ACs may occur over the surface of the brain around or around the skull base and over the pituitary gland. Most ACs are discovered incidentally because of a CT scan or MRI obtained for another reason and do not require treatment. On occasion however, some ACs enlarge and put pressure on adjacent neural structures such as the optic nerves, brainstem, cerebral cortex or pituitary gland and require surgical drainage or fenestration. This treatment is usually quite effective.

Astrocytoma

A primary brain tumor arising from the glial cells of the nervous system, specifically the astrocytes. These tumors are graded on a 3 or 4-point scale based on their differentiation and aggressiveness. The World Health Organization uses a 4-point scale: Grade 1 — pilocytic or low grade astrocytomas; Grade 2 — diffuse astrocytomas; Grade 3 — anaplastic (malignant) astrocytomas; Grade 4 — glioblastoma multiforme (most common and most malignant). In addition to these four tumor grades, astrocytomas may combine with oligodendrocytes to produce oligoastrocytoma and other variants. They may arise in the cerebral hemispheres, in the cerebellum, brainstem, optic nerves or spinal cord. Tumor-related symptoms depend on their location; for cerebral astrocytomas, the most common symptoms are seizures and headache. Treatment of astrocytomas usually involves surgical debulking, radiotherapy and chemotherapy with temazolamide. Learn more.

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B

Benign (Non-Malignant)

A benign tumor is one that lacks the malignant properties of a cancer. It does not grow in an unlimited, aggressive manner and does not metastasize (travel to other organs). Although many brain tumor types are considered histologically benign such as pituitary adenomas, chordomas, craniopharyngiomas and meningiomas, they can still be locally invasive, cause serious disability and be difficult to control with surgery alone.

Bitemporal Hemianopsia

It is a loss of peripheral vision in both eyes resulting from pressure on the optic chiasm, typically from a tumor such as a pituitary adenoma, craniopharyngioma or meningioma. The optic chiasm is located directly above the pituitary gland in the suprasellar cistern and is composed of crossing fibers from both optic nerves.

Brainstem

The lower, most primitive part of the brain which includes the midbrain, pons and medulla. The lower brainstem (medulla) transitions into the spinal cord. The brainstem is essential for many basic functions including breathing, heart rate and blood pressure regulation. All but two cranial nerves (the olfactory and optic nerves) arise from the brainstem.

Bromocriptine (Parlodel)

A short-acting dopamine agonist medication which suppresses prolactin production and is usually taken one to three times daily. It is used to treat prolactinomas prolactin secreting pituitary adenomas) and other causes of hyperprolactinemia. The medication lowers the prolactin level and causes shrinkage of the prolactinoma. Because of relatively frequent and unpleasant gastro-intestinal side effects (nausea), this drug is now used less often than Cabergoline (Dostinex®).

Buffalo Hump

An abnormal accumulation of adipose tissue (fat) in the upper back and lower neck, most often seen in patients with excess cortisol production from Cushing’s syndrome or Cushing’s disease (an ACTH-secreting pituitary adenoma). In patients with Cushing’s disease, other abnormal accumulations of fatty tissue can occur in the area between the neck and shoulders (supraclavicular fat pads) and in the trunk and abdominal area.

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C

Cabergoline (Dostinex®)

A long-acting dopamine agonist medication which suppresses prolactin production and is usually taken only twice per week. It is used to treat prolactinomas (prolactin secreting pituitary adenomas) and other causes of hyperprolactinemia. The medication usually lowers the prolactin level and causes shrinkage of the prolactinoma. It is now the drug of choice for patients with a prolactinoma because it is only taken twice per week and generally has fewer side effects than bromocriptine. It has also been shown to be effective in patients whose prolactinomas are resistant to bromocriptine therapy. The usual starting dose is 0.5 mg twice per week. The dose may be increased up to 1.0 mg twice per week. The major disadvantage of cabergoline is that it is somewhat more expensive than bromocriptine.

Carcinoma

A malignant tumor (cancer) that develops from epithelial cells that line organs such as the lungs, breast, stomach, colon, prostate and skin. Carcinomas tend to infiltrate into adjacent organs and tissues and can spread to other organs (metastasize) such as bone, liver, lung or brain.

Carotid Arteries

It is two large blood vessels that supply a majority of the brain with oxygenated blood from the heart. The carotid arteries course through the soft tissues of the neck and divide into the external and internal carotid arteries. The 4 segments of the internal carotid artery (ICA) include the cervical (in the upper neck), petrous (in the skull base), cavernous (within the cavernous sinus alongside the pituitary gland) and supra-clinoid or cerebral segments. The ICAs then bifurcate (divide) into the anterior and middle cerebral arteries and have connections through the Circle of Willis with the vertebro-basilar arterial complex (posterior circulation). Being aware of the location of the cavernous carotid arteries is important during endonasal surgery given their close proximity to the pituitary gland. Such localization is most easily done with the micro-doppler probe. Pituitary tumors and other skull base tumors such as meningiomas and chordomas can sometimes invade the cavernous sinus and surround the carotid arteries.

Cavernous Sinus

The two paired venous spaces located within the skull base in the sphenoid bone. These multi-compartmental spaces are surrounded by dura and located directly adjacent to the pituitary gland. Several critical structures pass through the cavernous sinuses including the internal carotid arteries on their way to the brain, as well as several cranial nerves including cranial nerves III (oculomotor), IV (trochlear) and VI (abducens) which are responsible for eye movements, as well as parts of cranial nerve V (trigeminal) which is responsible for facial sensation. Pituitary tumors and other skull base tumors such as meningiomas and chordomas can sometimes invade the cavernous sinus, surround the carotid arteries and cause impairment of the cranial nerve function with resultant double vision and/or facial pain or facial numbness.

Cerebrospinal Fluid (CSF)

A clear colorless fluid containing water, electrolytes, sugars and other molecules produced by the choroid plexus of the ventricles of the brain. CSF flows out of the fourth ventricle into the subarachnoid space which covers the brain and spinal cord. CSF appears to have multiple functions including 1) acting as a buffer to cushion the brain and spinal cord against mechanical insults and trauma, 2) providing nutrition (sugar and other nutrients) to the adjacent neural tissues, 3) for communication through neurotransmitters, hormones and cytokines that pass into the CSF, and 4) for waste disposal of the central nervous system metabolism products.

Cerebrospinal Fluid (CSF) leak

It is an abnormal flow of CSF from an opening or tear in the meninges (brain covering including the arachnoid and dura) that surround the brain. This dangerous situation can occur after surgery for a brain tumor, pituitary tumor or spinal tumor or can be caused by a head injury and skull fracture. Prompt repair of CSF leaks is indicated to prevent meningitis (CSF infection) and other potential complications.

Chiari Malformation

A congenital defect which causes part of the brain (the cerebellar tonsils) to be pushed through the opening in the base of the skull (foramen magnum) into the spinal canal.  If the malformation puts significant pressure on the lower brainstem or cervical spinal cord, symptoms can occur including headache, neck pain, numbness and tingling of the extremities (especially of the shoulders and arms), weakness, difficulty urinating and balance or incoordination.  In more severe cases, the Chiari malformation is associated with a syrinx (a fluid-filled cavity within the spinal cord) which can also contribute to the neurological problems described above.  Treatment of a symptomatic Chiari I malformation typically involves removal of bone at the skull base (sub-occipital craniectomy and upper cervical laminectomy) and expansion of the dura in the posterior fossa.  This operation has a success rate of alleviating symptoms and halting neurological deterioration of approximately 80%.

Chiasmal Compression

Pressure on the optic chiasm (crossing fibers of the optic nerves) typically from a Pituitary tumor or other tumor that can result in loss of peripheral vision known as a bitemporal hemianopsia.

Chordoma (Clival Chordoma)

Clival chordomas tumors are locally invasive tumors that arise in the base of the skull.

Clival chordomas are best treated with maximal surgical removal followed by focused radiotherapy. Fortunately, the majority of chordomas can be removed via the nose using an endonasal endoscopic approach.  At the Brain Tumor Center (BTC), we have the world’s best chordoma tumor surgeons with the largest endonasal experiences treating clival chordomas. By incorporating cutting edge technology and instrumentation with proven surgical experience, we make chordoma surgery safer, less invasive and more effective.

Clivus

A part of the skull base in the midline located below the sella turcica and forming the back wall of the sphenoid sinus; directly in front of the brainstem.

Cortisol

An essential hormone for dealing with stress produced by the adrenal glands in response to ACTH (secreted by the pituitary gland). Excess cortisol is produced in patients with Cushing’s Disease.

Cranial Nerves

There are 12 paired cranial nerves which arise from the brain or brainstem and which are responsible for a variety of critical neurological sensory and motor functions. They include:
CN I – olfactory nerves; for olfaction (sense of smell)
CN II – optic nerves; for sight
CN III – oculomotor nerves; for most eye movements
CN IV – trochlear nerves; for moving the eyes down and inward
CN V – trigeminal nerves; for facial sensation and muscles of mastication (chewing muscles)
CN VI – abducens nerves; for moving the eyes outward
CN VII – facial nerves; for facial muscle innervation
CN VIII – vestibulo-cochlear nerves – for hearing and balance
CN IX – glossopharyngeal nerves – for sensation of the posterior 1/3 of the tongue, tonsils and pharnynx, for swallowing and the gag reflex and for parasympathetic innervation of the parotid gland
CN X – vagal nerves – for muscles in the mouth and larynx and for parasympathetic innervation of many organs in the body
CN XI – spinal accessory nerves – for neck movements through the trapezius and sternocleidomastoid muscles
CN XII – hypoglossal nerves – for tongue movements

Craniectomy

A procedure in which a portion of the skull is removed to expose the brain and remove a tumor or other intracranial problem such as a hematoma (bleeding). The “bone flap” is not replaced at that time which can allow for brain swelling to subside. The bone may be replaced at a later time.

Craniopharyngioma

A benign tumor that arises near the pituitary gland and stalk and is typically both cystic and solid in structure. They occur most commonly in childhood and adolescence and in later adult life after age 50 years. They account for 10-15% of sellar and suprasellar tumors (tumors that occur in and above the pituitary gland) and 50-60% of sellar and suprasellar tumors in children. They are usually not discovered until they impinge upon important structures around them, and are frequently quite large (over 3 cm) when detected. They can cause loss of pituitary function (hypopituitarism), visual loss, headaches and other symptoms. Primary treatment is surgical by the endonasal route of supra-orbital route; additional therapy such as radiotherapy or radiosurgery and hormone replacement are often needed.

Cranioplasty

A surgical procedure in which a portion of the skull is replaced after prior craniectomy or brain injury with original bone or with a metallic or other synthetic prosthesis.

Craniotomy

A procedure in which a portion of the skull is removed to expose the brain and remove a tumor or other intracranial problem such as a hematoma (bleeding). The “bone flap” is replaced usually with titanium plates and screws after the completion of the procedure.

Cushing’s Disease

It is caused by an ACTH-secreting pituitary adenoma. This serious endocrinopathy is a subset of Cushing’s syndrome which refers to elevated blood cortisol levels.

Cushing’s syndrome

A syndrome of elevated blood cortisol levels from any cause which may include an ACTH-secreting pituitary adenoma (Cushing’s disease), an adrenal adenoma, ectopic ACTH production (e.g., from a small cell lung cancer), and steroid medications.

Cyst

It is a closed sac having a membrane separating it from nearby tissues. Cysts may contain fluids such as cerebrospinal fluid (CSF), necrotic (dead) tissue that is semi-solid or hemorrhage (blood products). A collection of pus is called an abscess, not a cyst. Relative to the pituitary gland and brain, the most common cystic problems include arachnoid cysts, cystic craniopharyngiomas, Rathke’s cleft cysts and hemangioblastomas.

Cystercerosis (Neurocysticercosis)

It is the most common parasitic infection of the central nervous system worldwide. It is caused by larvae of the tapeworm, Taenia solium, normally found in pork.

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D

DDAVP

A generic name for desmopressin acetate (Stimate®). Used in treating diabetes insipidus (DI), a temporary or permanent condition characterized by the production of excessive and dilute urine which results from damage to the posterior pituitary gland or the pituitary stalk. DDAVP may be given as a nasal spray, tablets or injection.

Decadron (Dexamethasone)

A potent synthetic glucocorticoid hormone and in the same class of hormones as the naturally produced cortisol. It is an anti-inflammatory and immunosuppressant. Its potency is about 40 times that of hydrocortisone (another glucocorticoid). In patients with brain tumors (primary or metastatic) and brain edema (swelling), dexamethasone is often used to counteract the swelling. Its side effects include elevated blood sugar (hyperglycemia), hypertension, increased risk of infections and poor wound healing.

Dexamethasone Suppression Test

It is to diagnose and differentiate among the various types of Cushing’s syndrome and other hyper-cortisolemic states.

Diabetes Insipidus (DI)

A condition of excessive and dilute urination resulting from lack of antidiuretic hormone (ADH). Such patients have excessive thirst and can become rapidly dehydrated unless they are adequately hydrated or the ADH is replaced by administering DDAVP. DI results from damage to the pituitary stalk, posterior pituitary gland or hypothalamus.

Diabetes Mellitus

It is a metabolic disorder that arises with hyperglycemia (high blood sugar) resulting from low levels of the hormone insulin or resistance to insulin’s effects. Common symptoms of diabetes mellitus are similar to that of diabetes insipidus (DI), frequent urination and pronounced thirst; however, they are not related disorders.

Diplopia

The double vision which in the case of skull base or brain tumors typically results from pressure or damage to cranial nerves III, IV or VI (oculomotor, trochlear or abducens) as they travel from the brainstem through the cavernous sinus and to the orbit.

Dostinex® (Cabergoline)

The trade name for cabergoline, a long-acting dopamine agonist medication and the treatment of choice for most patients with a prolactinoma.

Dura

From the Latin “hard mother”; the tough but flexible outermost of the three layers of the meninges surrounding the brain, pituitary gland and spinal cord. (The other two meningeal layers are the pia mater and the arachnoid.) The dura is routinely opened and closed during neurosurgical procedures. An inadequate closure can result in a cerebrospinal fluid leak and possible meningitis.

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E

Endocrine-Inactive Adenoma (Non-Functioning Adenoma)

A pituitary adenoma that does not result in excess hormone production. Instead these adenomas cause symptoms because of pressure on the normal pituitary gland and on structures near the pituitary such as the optic nerves and optic chiasm. Primary treatment is by endonasal transsphenoidal surgical removal.

Endocrinology

It is the practice of medicine dealing with hormonal disorders and the endocrine system. The endocrine system is composed primarily of the hypothalamus, pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries and testes.

Endonasal Surgery

By performing intracranial surgery through a nostril using the operating microscope or endoscope or both. Endonasal surgery is a subset of transsphenoidal surgery which means operating through the sphenoid sinus (behind the nasal cavity). Virtually all pituitary adenomas and Rathke’s cleft cysts, the majority of craniopharyngiomas and clival chordomas as well as many other tumor types such as suprasellar meningiomas and sinus carcinomas can now be removed through a nostril.

Ependymoma

One of the 3 major types of gliomas: astrocytomas, ependymomas and oligodendrogliomas. Ependymomas arise from the ependymal lining of the ventricles (fluid-filled chambers of the brain). Treatment of ependymomas usually involves surgical debulking, radiotherapy and sometimes chemotherapy.

Epidermoid Cyst

Epidermoid cysts are benign masses that can arise over the surfaces of the brain.

Epidermoid cyst surgery is required to remove symptomatic cysts; fortunately, most can be removed through one of several keyhole routes depending upon cyst location and size.  At the BTC, we have the best surgeon for epidermal cyst removal and have vast experience in minimally invasive surgical approaches for all types of brain and skull base tumors. By incorporating cutting edge technology and instrumentation with proven surgical experience, we make surgery safer, less invasive and more effective.

Esthesioneuroblastoma (Olfactory Neuroblastoma)

It is an uncommon brain tumor arising from the olfactory nerve that can cause headaches, nasal obstruction and nasal bleeding. Multi-modality treatment with surgery, radiotherapy and chemotherapy is typically indicated.

Estrogen

A hormone produced by the ovaries. Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) control production of sex hormones (estrogen and testosterone) as well as sperm and egg maturation and release. Also known as Estradiol (E2), estrogen is critical for female reproductive and sexual functioning and for bone structure. Estrogen, like other steroids, is derived from cholesterol.

Ethmoid Sinus

One of the air sinuses located adjacent to the nasal cavity. The ethmoid sinus and its multiple ethmoidal air cells sit above the nasal cavity, between the orbits and below the frontal fossa where the frontal lobes reside. The other paranasal sinuses are the paired maxillary sinuses and the sphenoid sinus.

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F

Fat Graft

In the case of endonasal pituitary surgery, if there is a defect in the dura and a spinal fluid leak seen at surgery a piece of fat may be harvested from a small abdominal incision and used to block the flow of CSF into the sphenoid sinus. Typically with a CSF leak, a multilayered closure is performed with other material which might include collagen sponge, tissue glue and a synthetic plate.

Follicle Stimulating Hormone (FSH)

It is produced in the pituitary gland; Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH ) control the production of sex hormones (estrogen and testosterone) as well as sperm and egg maturation and release.

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G

Gadolinium

It is a contrast agent given intravenously; often used when performing an MRI to help localize tumors; it is quite safe and does not contain iodine unlike the iodinated contrast agent used for CT scans (computed tomography).

Galactorrhea

A milky breast discharge occurring at anytime other than during normal breast feeding. Galactorrhea is most often seen in women with hyperprolactinemia (high blood levels of prolactin), especially in those with prolactinoma or other pituitary-related tumors. Galactorrhea often occurs in association with amenorrhea (absence of menstrual periods) because of the effect of high prolactin on LH and FSH release from the pituitary gland. Rarely men may also experience galactorrhea.

Gigantism

The condition of extreme body height and excessive growth typically occurring in adolescence as a result of a growth hormone secreting pituitary adenoma (acromegaly). The typical physique is of enlarged head and jaw with “frontal bossing” as well as large hands and feet.

Glioblastoma Multiforme (GBM)

Gliomas are common tumors that arise from the brain itself from glial cells.

The optimal treatment for most gliomas is maximal surgical removal. For patients with higher grade gliomas, surgery is followed by radiation therapy and chemotherapy. Fortunately, many if not most gliomas can be surgically removed through one of several keyhole routes depending upon tumor location and size.  At the BTC, we incorporate cutting-edge technology such as MRI fiber tractography, functional MRI and surgical navigation and awake craniotomy protocols, with proven surgical experience, to make glioma surgery safer, less invasive and more effective. We have a large experience in the comprehensive care of all types of gliomas including low grade astrocytomas, oligodendrogliomas, anaplastic astrocytomas and glioblastomas.  Our neurosurgeons work closely with our radiation oncologists, neuro-oncologists and neuropathologists to design the optimal treatment plan that incorporates the latest in radiotherapy techniques and tumor biomarker studies. By using comprehensive tumor histological subtyping and genomic sequencing, we are able to provide a personalized therapeutic approach for each patient. Our team can also facilitate participation in clinical trials using novel medical therapies for patients with gliomas.

Glioma

The most common type of brain tumor. They can occur at any age and in any part of the brain or spinal cord where glial cells (the support of the nervous system) are located. There are several types of gliomas and they range from the low grade to high grade (glioblastoma multiforme – GBM).

Growth Hormone (GH)

It is the principle pituitary hormone that regulates growth and metabolism. Its action is primarily carried out by IGF-1 which is made in the liver. GH also has direct actions on the blood vessels both extra-cranially and in the brain. GH is essential for normal growth and development but is also important as an adult for muscle mass, exercise capacity and general quality of life. GH deficiency is treatable by a daily injection of GH.

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H

Hemangioblastoma

It is a benign vascular tumor that is typically cystic and can occur throughout the central nervous system but found most frequently in the cerebellum, spinal cord and brainstem. Primary treatment of symptomatic hemangioblastomas is usually by surgical removal. Von Hippel Lindau syndrome is an autosomal dominant inherited disorder characterized by both benign hemangioblastomas of the central nervous system and retina as well as renal cell carcinoma, pancreatic cysts and tumors and other neuroendocrine tumors.

Hematoma

A collection of blood from abnormal bleeding. Intracranial hematomas may form over the surface of the dura (epidural), under the dura (subdural), under the arachnoid membrane (subarachnoid hemorrhage) or within the brain (intracerebral or intraparenchymal). Hematomas may arise from trauma, bleeding into a tumor, from hypertension, excessive anticoagulation medication or after intracranial surgery. Depending upon the size and location, a hematoma may require evacuation typically through a craniotomy. A chronic subdural hematoma is liquefied and can often be removed through a small hole in the bone and placement of a drainage catheter.

Hydrocephalus

It is a condition of excessive cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain. Hydrocephalus may cause increased intracranial pressure inside the skull and progressive enlargement of the head (in children), cognitive impairment and eventually if progressive, stupor and coma. Hydrocephalus is usually due to blockage of CSF outflow in the ventricles or in the subarachnoid space over the brain. It may occur after a brain infection (meningitis), brain hemorrhage or from a tumor compressing the ventricular system. Treatment is often by placing of a ventriculo-peritoneal (VP) shunt or in some case by a 3rd ventriculostomy.

Hydrocortisone

It is the pharmacological replacement of the natural stress hormone cortisol; used as an anti-inflammatory in the treatment of allergic reactions and as substitute for cortisol.

Hyperprolactinemia

The presence of abnormally high prolactin in the blood. Normal blood prolactin levels are less than 20 – 25 ng/ml. Prolactin secretion is inhibited by dopamine which is also known as prolactin inhibitory factor. Hyperprolactinaemia can result from multiple causes including pregnancy, hypothyroidism (low thyroid), kidney failure, medications, distortion of the pituitary gland and stalk from a tumor (“stalk compression”) and from a prolactinoma.

Hypogonadism

A defect of the reproductive system resulting in lack of function of the gonads (ovaries or testes). The gonads have two major functions: to produce hormones (testosterone, estradiol), and to produce gametes (eggs or sperm). Sex hormones deficiency can result in defective primary or secondary sexual development, infertility and loss of libido. Defective egg or sperm development results in infertility. pituitary adenomas and other tumors that impinge upon the pituitary gland can cause hypogonadism (a subset of hypopituitarism) by causing either decreased production of LH and FSH or by causing hyperprolactinemia which inhibits LH and FSH production.

Hypophysis

The pituitary gland also referred to as the “master gland” because it controls all hormonal function. The pituitary is located under the brain in the skull base, weighs less than one gram and measures one centimeter in width. Hormones when released by the pituitary into the blood stream have a dramatic and broad range of effects on growth and development, sexuality and reproductive function, metabolism, the response to stress and overall quality of life.

Hypophysitis (pituitary inflammation)

The inflammation of the pituitary gland and often the pituitary stalk. The etiology is uncertain but the results are typically permanent pituitary failure often with diabetes insipidus. Treatment is typically with hormone replacement therapy and high dose glucocorticoids (steroids) to reduce inflammation.

Hypopituitarism

The loss of pituitary gland hormonal function which may involve one or more of the hormonal axes (adrenal, thyroid, gonadal, etc). The term refers to both anterior and posterior pituitary gland dysfunction. Hypopituitarism may be temporary or permanent. Complete loss of all pituitary hormonal function is referred to as panhypopituitarsim.

Hypothalamus

This critical brain region is immediately below the thalamus and above the pituitary gland. The hypothalamus plays a major role in regulating body temperature, appetite, water balance, blood sugar and metabolism. Most of these functions are exerted through the connection to the pituitary gland by hypothalamic releasing hormones that travel down the pituitary stalk (infundibulum) to the gland.

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I

Inferior Petrosal Sinus Sampling (IPSS)

Please see Petrosal Sinus Sampling.

Insulin-Like Growth Factor-1 (IGF-1 or somatomedin-C)

A hormone made in the liver which acts as the second messenger for growth hormone; its molecular structure is similar to insulin. This is the principal hormone that regulates growth and metabolism and is controlled by GH secretion by the pituitary gland.

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K

Keyhole Craniotomy

Minimally invasive “keyhole” and conventional approaches are used to remove tumors over the surface of the brain or within the brain.Technical advances over the last two decades have allowed these approaches to become smaller, safer and more precise. Larger craniotomies are used when the tumor itself is very large and close to the brain surface, while smaller keyhole openings can be used for smaller surface tumors and most deeper tumors regardless of size.

For both keyhole and conventional craniotomies, a preoperative surgical navigation MRI or CT scan allows the scalp incision and bone opening to be tailored to the tumor location and facilitates safe and effective removal.Functional MRI and/or MRI tractography may also be used to determine the relationship of the tumor to critical brain regions and white matter tracts. Intra-operative ultrasound is also often used to help precisely localize deeply situated brain tumors.

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L

Leutinizing Hormone (LH)

It is produced by the pituitary gland. Along with Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH ) controls production of the sex hormones (estrogen and testosterone) as well as sperm and egg maturation and release.

Lipoma

A common benign tumor composed of fatty tissue, often under the skin. Lipomas are typically soft, moderately mobile and painless. They grow slowly and in most instances do not require treatment.

Lumbar Drain

A small flexible tube placed in the cerebrospinal fluid filled thecal sac of the lower back (lumbar area). The tube drains the fluid that surrounds the brain and spinal cord which relieves pressure. It may be used to drain and assess cerebrospinal fluid (CSF) for many different reasons. A lumbar drain may be inserted to allow healing at the operative site by decreasing CSF volume and pressure. A lumbar drain is usually inserted if a CSF leak persists with bed rest or if CSF is seen in the surgical field.

Lumbar Puncture

A diagnostic and/or therapeutic procedure to collect a sample of cerebrospinal fluid (CSF) for biochemical, microbiological, and cytological analysis. The most common purpose for a lumbar puncture is to collect cerebrospinal fluid to assess for an infection of the CSF (meningitis).

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M

Macroadenoma

Pituitary adenomas are the third most common intracranial tumor and arise from the pituitary gland.

Pituitary adenoma surgery is necessary for the great majority of symptomatic pituitary adenomas. Transsphenoidal surgical removal (via the nose) is typically the treatment of choice. Fortunately, pituitary adenoma surgery has had major technical advances over the last 15 years, including use of high-definition endoscopy, surgical navigation techniques and more effective skull base closure methods. At Pacific Pituitary Disorders Program, we have one of the world’s largest experiences in endonasal endoscopic transsphenoidal surgery for all types of pituitary adenomas including acromegaly, Cushing’s disease, prolactinomas, non-functional adenomas, pituitary apoplexy and residual or recurrent adenomas.  By incorporating cutting edge technology and instrumentation with proven surgical experienceof over 1600 endonasal surgeries, our pituitary tumor specialsts make pituitary surgery safer, less invasive and more effective.

Malignant

A severe and progressively worsening disease; used most frequently to describe a cancer and contrasted with a non-cancerous or “benign” tumor. Most malignancies are capable of invading adjacent tissues and may spread to distant tissues (metastasize).

Mass Effect

The local pressure from a tumor or bleeding (hematoma) on adjacent parts of the brain. Mass effect is diagnosed by an MRI or CT scan which shows where the mass is and what it is pushing on. Mass effect can lead to neurological symptoms such as weakness or loss of vision depending upon the location of the tumor or hematoma.

Maxillary Sinus

The largest air sinuses (paranasal sinus) located behind the cheekbones and below the orbits. These paired sinuses drain into the nasal cavity like the ethmoid and sphenoid sinuses.

Meningioma

A typically benign brain tumor although up to 5% can be aggressive or malignant. They are more common in women than men and can occur in all ages but are typically seen in middle-aged and older adults. Meningiomas may arise from any meningeal surface and are typically attached to the dura (outer layer of the meninges). Common locations include the convexity of the calvarium, frontal fossa (olfactory groove), tuberculum sella (near the pituitary gland), sphenoid wing and in other skull base areas. Primary treatment of symptomatic meningiomas is usually by surgical removal, often by a keyhole craniotomy or endonasal approach.

Meningitis

The inflammation or infection of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis most often develops from a viral or bacterial infection. While some forms of meningitis are mild and resolve on their own, meningitis is a potentially serious life-threatening condition. Bacterial meningitis can occur after intracranial surgery, especially in association with a leakage of cerebrospinal fluid (CSF leak). Prompt repair of the leak and antibiotics are required treatment.

Metastasis & Metastatic Tumor

Tumors that arise from a cancer from one organ and spread to a distant site such as the brain (also known as secondary brain tumors). The most frequent types of cancer that metastasize to the brain are lung, breast, melanoma, colon, renal (kidney) and thyroid. Treatment of metastatic brain tumors may involve surgical removal through a craniotomy, radiosurgery (SRS) or whole brain radiotherapy or chemotherapy. In many instances, all 3 of these treatments are needed.

Micro-Doppler Probe

This non-invasive device is used during surgery for localizing large arteries and veins (such as the carotid artery) of the brain.

Microadenoma

Pituitary adenomas are the third most common intracranial tumor and arise from the pituitary gland.

Pituitary adenoma surgery is necessary for the great majority of symptomatic pituitary adenomas. Transsphenoidal surgical removal (via the nose) is typically the treatment of choice. Fortunately, pituitary adenoma surgery has had major technical advances over the last 15 years, including use of high-definition endoscopy, surgical navigation techniques and more effective skull base closure methods. At Pacific Pituitary Disorders Program, we have one of the world’s largest experiences in endonasal endoscopic transsphenoidal surgery for all types of pituitary adenomas including acromegaly, Cushing’s disease, prolactinomas, non-functional adenomas, pituitary apoplexy and residual or recurrent adenomas.  By incorporating cutting edge technology and instrumentation with proven surgical experience of over 1600 endonasal surgeries, our pituitary tumor specialists make pituitary surgery safer, less invasive and more effective.

Minimally Invasive Brain Surgery

Surgery for brain tumors, skull base tumors and pituitary adenomas is a highly specialized area of neurosurgery that continues to rapidly evolve. At the BTC, we incorporate cutting edge technology and instrumentationwith proven surgical experience to make surgery safer, less invasive and more effective. Given advances over the last decade, most tumors can now be removed via a keyhole approach through a small craniotomy (bony opening in the skull) or the nostrils.

The ideal approach is determined by the specific tumor anatomy in each patient. These include the endonasal endoscopic (through the nostrils), supra-orbital (through the eyebrow), retromastoid (behind the ear), mini-pterional route (in front of the ear) and other keyhole and conventional craniotomies.

Regardless of the route chosen, our goals are to maximize tumor removal and minimize manipulation of critical structures, thereby avoiding complications and patient disfigurement, while promoting a more rapid, complete and less painful recovery.

Notably, endoscopic and other keyhole approaches are technically demanding, require specialized instrumentation and are not appropriate for all brain tumors. Consequently, there remains a role for conventional larger craniotomies especially when the tumor itself has created a path through the brain or bone. Our BTC Director, Dr. Daniel Kelly has extensive experience with both conventional and keyhole approaches totaling over 4000 such procedures over the past 20 years. This large experience allows us to provide a truly tailored approach best suited for each patient.

Explore Keyhole Surgical Approaches

Moon Face

An abnormal accumulation of fatty padding around the face. Symptoms and signs of Cushing’s syndrome and disease may include: change in body habitus and weight gain in face (moon face) above the collar bone (supraclavicular) and on back of neck (buffalo hump).

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Nelson’s Syndrome

It is caused by an ACTH-secreting adenoma in a patient with Cushing’s disease after undergoing bilateral adrenelectomies. As many as 25% or Cushing’s disease patients who undergo bilateral adrenalectomies will develop Nelson’s syndrome over the next 5 to 10 years. Removal of both adrenals eliminates production of cortisol, and the lack of cortisol’s negative feedback can allow these tumors to become quite aggressive and invasive. Nelson’s syndrome is relatively uncommon now given that bilateral adrenalectomy is now used infrequently in the treatment of patients with Cushing’s disease.

Neoplasm

It an abnormal proliferation of cells in a tissue or organ which encompasses the terms of tumor, adenoma (benign) and carcinoma (malignant).

Neurofibromatosis

Neurofibromatosis is an autosomal dominant genetic disorder. It encompasses a set of distinct genetic disorders that cause tumors to grow along nerves and, in addition, can affect the development of non-nervous tissues such as bones and skin. The tumors can grow anywhere on or in the body.

Neurosurgery

The practice of medicine devoted to the surgical management of disorders of the brain, spinal cord, vertebral column and peripheral nerve.

Non-Functioning Adenoma

Pituitary adenomas that do not produce excess hormones. Instead they typically cause symptoms due to pressure on the normal pituitary gland and/or structures around the pituitary such as the optic nerves and optic chiasm, leading to headaches, visual loss and pituitary failure. Primary treatment of symptomatic non-functioning adenomas is endonasal endoscopic removal.

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Octreotide

The generic term for an octapeptide hormone that mimics natural somatostatin. This drug is used to inhibit growth hormone in the treatment of acromegaly. Also known by the trade names of Sandostatin.

Olfactory Groove Meningioma

A meningioma that arises along the olfactory groove in the frontal fossa of the brain (under the frontal lobes in the midline and above the ethmoid air sinus). Primary treatment is typically surgical removal through a craniotomy such as a supra-orbital eyebrow approach.

Olfactory Neuroblastoma

An uncommon brain tumor arising from the olfactory nerve that can cause headaches, nasal obstruction and nasal bleeding. Multi-modality treatment with surgery, radiotherapy and chemotherapy is typically indicated.

Oligodendroglioma

Gliomas are common tumors that arise from the brain itself from glial cells.

The optimal treatment for most gliomas is maximal surgical removal. For patients with higher grade gliomas, surgery is followed by radiation therapy and chemotherapy. Fortunately, many if not most gliomas can be surgically removed through one of several keyhole routes depending upon tumor location and size.  At the BTC, we incorporate cutting-edge technology such as MRI fiber tractography, functional MRI and surgical navigation and awake craniotomy protocols, with proven surgical experience, to make glioma surgery safer, less invasive and more effective. We have a large experience in the comprehensive care of all types of gliomas including low grade astrocytomas, oligodendrogliomas, anaplastic astrocytomas and glioblastomas.  Our neurosurgeons work closely with our radiation oncologists, neuro-oncologists and neuropathologists to design the optimal treatment plan that incorporates the latest in radiotherapy techniques and tumor biomarker studies. By using comprehensive tumor histological subtyping and genomic sequencing, we are able to provide a personalized therapeutic approach for each patient. Our team can also facilitate participation in clinical trials using novel medical therapies for patients with gliomas.

Optic Glioma

A glioma of the optic nerves or optic chiasm, typically a low grade astrocytoma. One or both of the optic nerves or optic chiasm may be involved resulting in progressive visual loss.

Optic Nerve & Optic Chiasm

The 2nd cranial nerves responsible for transmitting visual information from the retina to the occipital cortex of the brain. The optic nerves exit the orbit and pass through the optic canals (in the skull base) and into the intracranial space. A portion of each optic nerve crosses the midline above the pituitary gland to form the optic chiasm. Pressure on an optic nerve from a tumor causes monocular visual loss (in one eye only). Pressure from a tumor on the optic chiasm causes loss of peripheral vision in both eyes (also known as a bitemporal hemianopsia).

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Panhypopituitarism

It refers to complete loss of all pituitary function requiring hormone replacement therapy. Patients with panhypopituitarism should carry a Medic Alert Bracelet with them to notify health care personnel of this problem in case of an emergency.

Papilledema

The swelling of the optic nerves as seen through the back of the eye with a fundiscopic exam (eye exam). It is typically caused by increased intracranial pressure from a brain tumor or other brain mass and is typically bilateral.

Parlodel

A short-acting dopamine agonist medication which suppresses prolactin production and is usually taken one to three times daily. It is used to treat prolactinomas (prolactin secreting pituitary adenomas) and other causes of hyperprolactinemia. The medication lowers the prolactin level and causes shrinkage of the prolactinoma. Because of relatively frequent and unpleasant gastro-intestinal side effects (nausea), this drug is now used less often than Cabergoline (Dostinex).

Petrosal Sinus Sampling

It is an interventional neuroradiology procedure used in patients with ACTH-dependent Cushing’s syndrome to distinguish between Cushing’s disease (from a pituitary adenoma) and ectopic Cushing’s (typically from a lung carcinoma). IPSS should only be performed by experienced neuro-radiologists and only after an initial and thorough endocrine evaluation. The procedure is usually performed under general anesthesia and involves injection of corticotropin releasing hormone (CRH) then followed over the next 10 minutes by multiple measures of serum ACTH levels in the right and left inferior petrosal sinuses and in the peripheral blood.

Pilocytic Astrocytoma

A slow growing benign glioma that occurs primarily in children (in the first 20 years) and involves the midline, basal and posterior fossa structures. These tumors are often partly cystic (filled with fluid) and solid and tend to be well circumscribed. Primary treatment usually involves surgical removal.

Pituitary Adenoma

A benign and typically slow growing tumors of the pituitary gland. They are the third most common intracranial tumor after gliomas and meningiomas.

Pituitary Apoplexy

The acute bleeding and infarction of a pituitary adenoma which may cause rapid onset of headache, visual loss, double vision and/or pituitary failure. Urgent endonasal surgery is generally required.

Pituitary Failure

It is loss or under functioning of the pituitary gland in which one or more functions of the pituitary gland hormones are deficient.

Pituitary Gland

It is also referred to as the “master gland” because it controls all hormonal function. The pituitary is located under the brain in the skull base, weighs less than one gram and measures one centimeter in width. Hormones when released by the pituitary into the blood stream have a dramatic and broad range of effects on growth and development, sexuality and reproductive function, metabolism, the response to stress and overall quality of life.

Pituitary Hormones

The essential life-sustaining substances produced by the anterior and posterior lobes of the pituitary gland: thyroid stimulating hormone (TSH), ACTH, follicle stimulating hormone (FSH), leutenizing hormone, growth hormone (GH), and prolactin. The posterior pituitary gland secretes vasopressin and oxytocin.

Pituitary Stalk

This critical but delicate neurovascular structure (comprised of nerves and blood vessels) is the connection between the hypothalamus and the pituitary gland. It carries the hypothalamic releasing hormones for the anterior pituitary gland and also axons from the magnocellular neuro-secretory cells of the hypothalamus to the posterior pituitary where they release their hormones oxytocin and antidiuretic hormone (ADH) into the blood.

Posterior Fossa

The lower portion of the skull which contains the cerebellum (for coordination and balance) and the brainstem.

Prednisone

A synthetic glucocorticoid steroid drug usually taken orally as replacement for adrenal insufficiency (lack of cortisol production) and also given for its anti-inflammatory effects for disorders such as rheumatoid arthritis, inflammatory bowel disease and asthma.

Prolactin

A hormone produced by the pituitary gland which stimulates lactogenesis or milk production after giving birth.

Prolactinoma

These common adenomas secrete excessive prolactin and generally have different presentations in women and men. The normal prolactin level is generally less than 20 ng/ml. In most women with prolactinomas, the tumors are detected when they are smaller (microadenomas) and the prolactin level is only moderately elevated (50 – 300 ng/ml). In contrast, in men prolactinomas are often detected when they larger (macroadenomas) and often have prolactin levels over 500 – 1000 ng/ml.

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Radiosurgery

A single high dose of focused radiation delivered to a tumor or vascular malformation. Radiosurgery is frequently used to treat brain, pituitary and skull base tumors that are not amenable to complete surgical removal. Radiosurgery can be delivered by a linear accelerator (Trilogy or Novalis) or by the Gamma Knife or Cyberknife; the effectiveness of these different forms of radiosurgery in terms of stopping tumor growth appears to be relatively equal. For tumors that are less than 2 or 3 mm away from the optic nerves or optic chiasm, fractionated (multiple lower dose radiation treatments) stereotactic radiation (SRT) is typically indicated to avoid damage to the optic nerves.

Radiotherapy

The multiple doses of radiation therapy given to treat a tumor or vascular malformation. Currently, most radiotherapy is given in focused fashion (stereotactic radiotherapy – SRT) although at times, whole brain radiation is still indicated for some malignant brain tumors such as glioblastoma or metastatic brain tumors.

Rathke’s Cleft Cyst

A benign cystic collection of fluid that forms in the pituitary gland. These cysts may become symptomatic from headaches, pituitary failure (hypopituitarism) or visual loss and require removal by endonasal surgery.

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Schwannoma

A benign nerve sheath tumor that most often arises from cranial nerve 8 (the vestibule-cochlear nerve) or cranial nerve 5 (the trigeminal nerve). Treatment for acoustic and trigeminal schwannomas is typically by surgical removal through a retro-sigmoid approach or other skull base approach. Alternatively in some cases or in patients in whom a total tumor removal is not possible, they can be effectively treated with radiosurgery or stereotactic radiotherapy.

Sella Turcica

The bony depression in the sphenoid bone of skull base that houses the pituitary gland; also known as the pituitary fossa; derived from the Latin for “Turkish saddle”.

Somatomedin-C

A hormone made in the liver which acts as the second messenger for growth hormone; its molecular structure is similar to insulin. This is the principle hormone that regulates growth and metabolism and is controlled by GH secretion by the pituitary gland.

Sphenoid Bone

The part of the skull base, located in front of the temporal bone and shaped like a wedge or butterfly. In the midline it joins the nasal septum. Behind the sphenoid keel is the sphenoid sinus through which endonasal transsphenoidal surgery is performed.

Sphenoid Sinus

A midline air sinus behind the nasal cavity and in front of the sella turcica and clivus and below the frontal fossa and frontal lobes. The other paranasal sinuses include the ethmoid and maxillary sinuses which are all lined with mucous-secreting cells. The sphenoid sinus is the sinus through which endonasal transsphenoidal surgery is performed.

Sphenoid Sinus Carcinoma

A relatively uncommon neoplasm of the sphenoid sinus (accounting for approximately 1–2% of all paranasal sinus tumors). They tend to be locally invasive and their aggressive nature typically warrants multimodality treatment including endonasal transsphenoidal surgical debulking, radiotherapy, and chemotherapy in some cases.

Stalk Effect

An elevated blood prolactin level (hyperprolactinemia) occurring as a result of tumors or other masses within or near the pituitary gland and stalk that block delivery of dopamine (a neurotransmitter) from the hypothalamus to the prolactin secreting cells of the pituitary. Stalk effect hyperprolactinemia is seen most often with pituitary adenomas, craniopharyngiomas and Rathke’s cleft cysts. The elevation in prolactin is typically in the range of 30 to 150 ng/ml (normal range is < 20 ng/ml). Prolactin levels greater than 200 ng/ml are almost always due to a prolactinoma.

Stereotactic Radiotherapy

See Radiotherapy.

Striae

The irregular areas of skin that appear as bands, stripes, or lines. Striae are seen when a person grows or gains weight rapidly or has certain diseases or conditions, most notably Cushing’s disease or other causes of excess glucocorticoids (steroids). They most commonly are located on the breasts, hips, thighs, buttocks, abdomen and flank.

Subdural Hematoma

A collection of blood in the subdural space under the dura and over the brain surface. A SDH may form as a result of traumatic brain injury or after surgery. An acute subdural hematoma typically requires surgical evacuation through a craniotomy.

Suprasellar

The area above the sella turcica (pituitary fossa). Key structures in this area above the pituitary gland include the optic chiasm and optic nerves, the pituitary stalk (infundibulum) and the anterior cerebral arteries which arise from the internal carotid arteries.

Surgical Navigation

Like “GPS for the brain”. This technology is used for surgical planning and allows for more precise tumor localization before and during surgery. It allows the surgeon to know where the tumor is in relation to other critical brain structures.

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Temazolamide

An oral alkylating agent (chemotherapy) used in the treatment of high-grade gliomas (glioblastoma and anaplastic astrocytoma) and other malignant brain tumors and cancers. It is relatively effective and has fewer side effects than many other chemotherapies.

Testosterone

A steroid hormone produced predominantly in the testes of men but also in lesser amounts in the ovaries of women. Testosterone plays key roles in sexual function, libido, red blood cell production, bone health and quality of life. Hypogonadism with low testosterone is treatable with synthetic testosterone administered as a patch, gel or injection. On average, men produce about eight to ten times more testosterone than women.

Thyroid Stimulating Hormone

The pituitary hormone that stimulates the thyroid gland to release thyroid hormone (thyroxin). TSH is produced when the hypothalamus releases a substance called thyrotropin-releasing hormone (TRH). TRH then triggers the pituitary gland to release TSH.

Thyroxin

Thyroxin: This is often abbreviated as T4 (3:5,3′:5′ tetra­iodothyronine) is the major hormone secreted by the follicular cells of the thyroid gland and is under control from thyroid stimulating hormone (TSH) produced by the pituitary gland.

Transsphenoidal Surgery

A surgical approach through the nasal cavity and the sphenoid sinus to reach the area of the skull base (sella turcica) where the pituitary gland resides. Variations of the transsphenoidal approach include the sublabial route (under the lip) and more recently the endonasal approach (via a nostril). The endonasal endoscopic approach is rapidly becoming the preferred method to remove pituitary adenomas and related tumors in and around the pituitary gland.

Trigeminal Schwannoma

These benign nerve sheath tumors of the 5th cranial nerve are less common than acoustic schwannomas. They generally arise in Meckel’s cave in the pre-pontine space and typically cause facial pain (trigeminal neuralgia). As they enlarge they can grow further into the cavernous sinus or into the posterior fossa, causing double vision, loss of coordination and other symptoms of brainstem compression. Primary treatment is usually surgical removal.

Tuberculum Sellae Meningioma

A meningioma arising along the front of the sella turcica and above the pituitary gland on the sphenoid bone in the midline; these typically benign tumors cause gradual visual loss from optic nerve and optic chiasm compression. Primary treatment is by endonasal or supra-orbital craniotomy removal.

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Urinary Free Cortisol Test

It is used to evaluate for increased cortisol production in patients with possible Cushing’s syndrome or Cushing’s disease. A 24-hour urine sample is collected and the urine cortisol measurement then directly reflects the blood level of cortisol produced over that 24-hour period.

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Visual Field Testing

It is an important tool used by ophthalmologists, neurologists and neurosurgeons to detect and monitor visual loss which may be caused by brain or pituitary tumors or other disease that effect the optic pathways such as multiple sclerosis or glaucoma. Specific types of visual field loss help localize where a tumor resides such as a bitemporal visual field loss that occurs with pressure on the optic chiasm.

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