Transcript Pituitary gland

Pituitary gland
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 500–600 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
 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
 On average, the female gland is almost 20% heavier
than the male gland primarily because of relative
differences 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
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
The oculomotor nerve, trochlear nerve, and first 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
Pituitary tumors
Classifications:
a. 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,mening
ioma,optic nerve glioma
3.metastatic tumors
4.tumor like conditions(abscess)
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)
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
Signs & symptoms
Symptoms
Headache,nausea &vomiting,visual loss, short
stature,mental problems,diplopia
Signs
Papilledema ,visual defect,endocrine
dysfunction,cranial nerve palsy,psychatric
abnormality
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)
Treatment of hydrocephalus
Ommaya reservior
Radiotherapy
Linear accelerator
Gamma knife radiosurgery
Pituitary adenoma
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
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)
Adenoma
 Arise from adenohypophyseal cells
 10-15% of intracranial tu.
 Benign tu. Mostly,slow-growing
1. Adenoma with no apparent hor. Func.(20%)
2. Secretory
adenoma(prolactinoma,GH,TSH,ACTH,FSH/LH
adenoma
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.
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,oligospermia)
Hyperprolactinoma suppresses the hypothalamic –pituitarygonadal axis) leading to hypogonadism in both sexes
DIAGNOSIS
 Endocrine testing
1.fasting level of prolactine(>150ng/ml indicate
that the cause pit.adenoma, if it >1000ng/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)
Neuroimaging studies
C.T SCAN of sella with thin slices(1.5-2 mm)plus
contrast ,to exclude ac. Haemorrhage.
MRI of sellar & parasellar(<2.5mm slices)
Cerebral angiography or MRI angio to exclude
aneurysms.
TREATMENT
Mode of treatment depend on :
1.size of tumor
2.the level of serum prolactin.
3.the patient age & overall health.
4.The patient`s tolerance of or compliance with
medical therapy.
5.the patient desires fertility.
6.surgical risk factors
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. (<500 ng/ml),who desires pregnancy.
3. A Woman with macroprolactinoma who desire pregnancy.
4.Macroprolactinoma with s.prolactin>500ng/ml
5.Pituitary apoplexy as a complication of prolactinoma>
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
SURGICAL TREATMENT
Craniotomy (rt. Frontal)
Trans-sphenoidal & transnasal approach
craniotomy
transsphenoidal
COMPLICATIONS OF TRANS-SPHENOIDAL
1.C.S.F leak
2.Meningitis
3.Hypopituitarism & Diabetes insipidus
4.pneumocephalus
RADIOTHERAPY:
1.conventional external radiation
Adverse effect(hypopituitarysm, optic nerve or
chiasmal injury,brain
radionecrosis,carcinogenesis)
2.stereotactic radiosurgery (GAMMA KNIFE
RADIOSURGERY).
Indication(microadenoma or macroadenoma<5
cm)
Gamma knife
Pituitary apoplexy
Acute haemmorrhagic necrosis of a pituitary
adenoma&adjacent pituitary tiss.
Predisposing factors:pregnency,endocrinologic
manipulations(estrogen
adminstration,bromocriptine
medication),H.injury,chronic
cough&sneezing,anticoagulant drugs,cerebral
angio.,radiotherapy
Symptoms &signs
Headache,nausea & vomiting, diplopia&visual
impairment, compression of cranial n.s in one or
both cavernous sinuses,ophthalmoplegia,
meningeal irritation,photophobia
Diagnosis(MRA,ANGIO,CT,CLINICAL)
Treatment :
surgery
Acromegaly
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.
TREATMENT ALGORITHM
Neurosurgery 56:877-885, 2005)SRL=Ssomatostatin receptor ligand ,DA=dopamine agonist)
Indications for surgery
include
 active acromegaly
 visual loss and other forms of mass effect
 pituitary tumor apoplexy
 failure of other therapies (medical,
radiation).
 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
 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.
 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
 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.
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
Radiotherapy
Conventional radiotherapy
Stereotactic radiosurgery
 Remission rate (50-60%)
 Remission rate(17-96%)
 Time of remission delayed
 faster growth hormone
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)
hypersecretion decline.(2y)
 requires a well defined
target volume.
 be used as an alternative
primary treatment to
surgery.
 Hypopituitarism(0-33%)
Optic neuropathy, radionecrosis, vascular injury
were much lower in gamma knife than
conventional radiothearapy
Pre.
Post
Post medical.