Pituitary gland

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Pituitary gland
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Gross anatomy of the pituitary gland

• The average weight of the pituitary gland at
  birth is about 100 mg. Rapid growth occurs in
  childhood, followed by slower growth until the
  adult weight (approximately 500600 mg) is
  attained in the latter part of the second decade.
  The adult hypophysis measures approximately 10 mm
  in length, 10 to 15 mm in width, and about 5 mm
  in height

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• Although the adult hypophysis typically measures
  less than 1 cm in its greatest dimension and
  weighs less than 1 g, its small size gives a
  wrong idea about its importance and complexity
• Embryogenesis of the pituitary gland
• The pituitary gland originates from two discrete
  parts of the developing embryo ,(neural
  epithelial)
• The ant. Lobe develop from the roof of the
  mouth(epith.)and called adenohypophysis
• The post. Lobe develop from the
  brain(neural)called neurohypophysis

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• On average, the female gland is almost 20
  heavier than the male gland primarily because of
  relative di?erences in the size of the pars
  distalis(adenohypophysis).
• Furthermore, the weight of the gland increases
  by 12 to 100 during pregnancy because of
  enlargement of the pars distalis.
• the size of the pars nervosa remains relatively
  constant.
• The volume of the pituitary gland decreases with
  aging

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• The pituitary gland derives its blood supply from
  two groups of arteries. The superior hypophyseal
  artery (SHA) primarily supplies the anterior
  lobe, whereas the inferior hypophyseal artery
  (IHA) is primarily related to the pars nervosa.
  The SHA can arise from the supraclinoid portion
  of the internal carotid artery (ICA) or from the
  posterior communicating artery, whereas the IHA
  arises from the meningohypophyseal trunk, a
  branch of the cavernous segment of the ICA

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The oculomotor nerve, trochlear nerve, and ?rst
two divisions of the trigeminal nerve are
embedded in the lateral wall of the cavernous
sinus, lying between the endothelial lining and
the dura mater, whereas the abducens nerve is
contained within the sinus itself
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Pituitary tumors
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Classificationsa. classification of pit.tumors
and tumor like conditions

• 1.tumors derived from adenohypophyseal
  cells(adenoma, carcinoma)
• 2.other primary tumors of sella
  turcica.(angioma,craniopharyngioma,meningioma,opti
  c nerve glioma
• 3.metastatic tumors
• 4.tumor like conditions(abscess)

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craniophryngioma

• Arise from anterior superior margin of pituitary
  gland.
• Lined by stratified squamouse epithelium
• All CP had solid and cyctic part,contain
  cholestrol crystal (machine oil)
• CP donot undergo malignant degeneration but
  malignant behaviour,difficult cure (C.P adherant
  to the major art. At the base of the brain(int.
  carotid)

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craniophryngioma

• Calcification in plain x ray
• 54 in childhood ,20, in adult ,
• 2.5 -4 of all brain tumor
• 9 of children brain tu.
• ,peak incidence age 5-10 year
• 55-85 five years survival rate
• 5-10- mortality due to hypothalamic injurey
• High recurrence rate in 1st 1-3 years

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Signs symptoms

• Symptoms
• Headache,nausea vomiting,visual loss, short
• stature,mental problems,diplopia
• Signs
• Papilledema ,visual defect,endocrine
  dysfunction,cranial nerve palsy,psychatric
  abnormality

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Management

• Diagnosis
• Plain x-ray, C.T , M.R.I, endocrine assessment
• Treatment
• Surgery(hydrocephalus,cyst drainage)
• Medical replacement(steroids,A.D.H replacement
  with fluid)
• Radiotherapy(better results in children than
  adults)

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Treatment of hydrocephalus
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Ommaya reservior
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Radiotherapy

• Linear accelerator

• Gamma knife radiosurgery

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Pituitary adenoma
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b.classification of pituitary adenomas according
to endocrine function

• -SECRETORY
• 1.prolactinoma
• 2.GH adenoma
• 3.ACTH adenoma
• 4.FSH/LH adenoma
• 5.T.S.H adenoma
• 6.plurihormonal adenoma(more than 1 hormone
  secretion
• -ADENOMA WITH NO APPERANT HORMONAL FUNCTION
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c. Classification according to size on
radiographic appearance

• Grade-0 intrapit. Adenoma ,diam.less than 1
  cm,normal sella
• Grade-1 intrapit.ad.,diam.less than 1 cm,focal
  bulging or minor changes in sellar shape
• Grade-2 intrasellar adenoma,diam. More than 1
  cm,enlarge sella, no erosion
• Grade-3 diffuse ad.,diam more than 1 cm,enlarge
  sella, localized erosion
• Grade-4 invasive ad.,diam more than1 cm,extensive
  destruction of bony struc.(gohst sella)

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Adenoma

• Arise from adenohypophyseal cells
• 10-15 of intracranial tu.
• Benign tu. Mostly,slow-growing
• Adenoma with no apparent hor. Func.(20)
• Secretory adenoma(prolactinoma,GH,TSH,ACTH,FSH/LH
  adenoma

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PROLACTINOMA

• Most common functional pituitary tu., accounting
  for approximately 25 of all pit. Tu. 3 of all
  intracranial tumors
• Prolactin level elevated(200-300ng/ml) ,lower
  levels may be found if there is other tumors
  compressing the stalk and interrupt the flow of
  inhibitory dopamine.

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Clinical presentation

• Mass effect (visual field defect(bitemporal
  hemianopia),impaired acuity,headache,rarely
  3rd,4th,6th nerve palsies,hydrocephalus, other
  endocrinological symp.)
• women symptoms(primary or secondary amenorrhoea
  and infertility, galactorrhoea)
• Men symptoms(decreased libido,impotence,oligosperm
  ia)
• Hyperprolactinoma suppresses the hypothalamic
  pituitary-gonadal axis) leading to hypogonadism
  in both sexes

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DIAGNOSIS

• Endocrine testing
• 1.fasting level of prolactine(gt150ng/ml indicate
  that the cause pit.adenoma, if it gt1000ng/ml ,it
  signify the invasiveness of tu. that extend to
  cavernous sinus)
• 2. other hormonal assessment(pit.-thyroid
  ,pit.-gonadal(FSH-LH,testosterone),pit-adrenal(a.m
  cortisol),antidiuretic hor,(urine serum
  electrolytes)

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Neuroimaging studies

• C.T SCAN of sella with thin slices(1.5-2 mm)plus
  contrast ,to exclude ac. Haemorrhage.
• MRI of sellar parasellar(lt2.5mm slices)
• Cerebral angiography or MRI angio to exclude
  aneurysms.

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TREATMENTMode of treatment depend on

• 1.size of tumor
• 2.the level of serum prolactin.
• 3.the patient age overall health.
• 4.The patients tolerance of or compliance with
  medical therapy.
• 5.the patient desires fertility.
• 6.surgical risk factors

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Indications of surgical treatment of prolactinoma

• 1.Non invasive tu. With prolactine
  level(150-500ng/ml) and patient not wish to take
  long term medications.
• 2.A woman with non invasive tu.,prl. (lt500
  ng/ml),who desires pregnancy.
• 3. A Woman with macroprolactinoma who desire
  pregnancy.
• 4.Macroprolactinoma with s.prolactingt500ng/ml
• 5.Pituitary apoplexy as a complication of
  prolactinomagt
• 6.A prolactinoma in pregnant patient causing mass
  effect( visual loss)
• 7.A prolactinom that is not respond to medical
  treatment
• 8.A recurrent prolactinoma

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SURGICAL TREATMENT

• Craniotomy (rt. Frontal)
• Trans-sphenoidal transnasal approach

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craniotomy
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transsphenoidal
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COMPLICATIONS OF TRANS-SPHENOIDAL

• 1.C.S.F leak
• 2.Meningitis
• 3.Hypopituitarism Diabetes insipidus
• 4.pneumocephalus

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RADIOTHERAPY

• 1.conventional external radiation
• Adverse effect(hypopituitarysm, optic nerve or
  chiasmal injury,brain radionecrosis,carcinogenesis
  )

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• 2.stereotactic radiosurgery (GAMMA KNIFE
  RADIOSURGERY).
• Indication(microadenoma or macroadenomalt5 cm)

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Gamma knife
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Pituitary apoplexy

• Acute haemmorrhagic necrosis of a pituitary
  adenomaadjacent pituitary tiss.
• Predisposing factorspregnency,endocrinologic
  manipulations(estrogen adminstration,bromocriptine
  medication),H.injury,chronic coughsneezing,antic
  oagulant drugs,cerebral angio.,radiotherapy

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Symptoms signs

• Headache,nausea vomiting, diplopiavisual
  impairment, compression of cranial n.s in one or
  both cavernous sinuses,ophthalmoplegia, meningeal
  irritation,photophobia
• Diagnosis(MRA,ANGIO,CT,CLINICAL)
• Treatment
• surgery

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Acromegaly
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The aims of acromegaly treatment

• (1) to control clinical signs while preserving
  pituitary function with as minimal adverse
  effects as possible.
• (2) to normalize excessive growth hormone (GH)
  and IGF-1 secretion as quickly as possible,
  thereby achieving biochemical control
• (3) to avoid the expansion of the tumor volume
  and if possible reduce tumor size in order to
  relieve any symptom due to tumor mass.

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TREATMENT ALGORITHM
Neurosurgery 56877-885, 2005)SRLSsomatostatin
receptor ligand ,DAdopamine agonist)
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Indications for surgery include

• active acromegaly
• visual loss and other forms of mass effect
• pituitary tumor apoplexy
• failure of other therapies (medical, radiation).
  

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• visual compromise develops quite slowly and
  gradually
• surgical decompression of visual pathways is
  usually recommended unless the compression can be
  resolved by medical treatment.
• Undisputedly, the most rapid and reliable relief
  from optic nerve and chiasmal compression is
  being achieved by surgery, which is particularly
  appreciated if severe loss of vision occurred
  acutely, as in pituitary apoplexy

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• Hormonal oversecretion for patients with
  secretory pituitary adenoma increasing the
  morbidity and mortality.
• Clinical diagnosis of these diseases is
  generally considered an indication for surgery.
• Because surgery is still generally considered
  the most rapidly acting and cheapest long-term
  solution for most patients.

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• recent data suggest that hypopituitarism can also
  be considered an indication for surgery since
  pituitary function may be improved following
  decompression of the gland by selective tumour
  resection

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• A conservative approach is usually recommended in
  incidentally detected lesions, which became more
  frequent with the widespread availability of MR
  imaging.

BUT the progression of a tumour, which is
clearly documented in the MR, is another
indication to surgically attack a lesion that has
already shown an increase in size.
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Re-operations should be strongly considered if

• a resectable lesion has not been excised
  satisfactorily by the primary intervention
• patients with recurrent disease, if adjunctive
  medical or radiation therapy failed to achieve
  control of the adenoma
• in symptomatic progressions of residual tumours.
  It seems easier for an expert neurosurgeon with
  an excellent success and a low complication rate
  to recommend an operation for a pituitary tumour

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Radiotherapy

• Stereotactic radiosurgery

• Conventional radiotherapy

• Remission rate (50-60)
• Time of remission delayed by several years(10y).
• Propsed for patients with aggressive adenoma when
  surgery cannot allow biochemical control.
• Hypopituitarism increases with time
  (50-80),also its more with previosly altered
  pit. Function(by surgery)

• Remission rate(17-96)
• faster growth hormone hypersecretion decline.(2y)
• requires a well defined target volume.
• be used as an alternative primary treatment to
  surgery.
• Hypopituitarism(0-33)

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• Optic neuropathy, radionecrosis, vascular injury
• were much lower in gamma knife than
• conventional radiothearapy

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Pre.
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Post
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Post medical.