Pituitary Guerin Flashcards
anterior pituitary cell types
somatotrophs
mammosomatotrophs
lactotrophs
corticotrophs
thyrotrophs
gonadotrophs
somatotrophs secrete
GH
mammosomatotrophs secrete
prolactin and GH
lactrotrophs secrete
prolacting
corticotrophs secrete
ACTH and POMC, and melanocyte stimulating hormone (MSH)
thyrotrophs secrete
TSH
gonadotrophs secrete
FSH and LH
local mass effect pituitary
radiographic abnormalities of sella turcica
compression of optic nerves and chiasm–> visual fiedl abnormalities
-lateral (temporal) visual fields
signs and symptoms of elevated intracranial pressure
-HA, nausea, vomitin
pituitrary adenoma, if really big can cause
hypopituitarism
pituitary adenoma peak age and size
35-60 y/o
if above 1 cm then macroadenoma if below 1 cm then microadenoma
atypical adenomas
more likely to behave aggressively
Gross typical pituitary adenoma
- soft and well circumscribed
- when small, confined to sella turcica
- as expand, they erode sella turcica and anterior clinoid processes
larger ones extend superiorly and often compress the optic chiasm and adjcaent structures like cranial nerves
pituitary adenoma histology
uniform, polygonal cells in sheets or cords
- reticulin is sparse
- mitotic activity is usually sparse
- cytoplasm may be acidophilic, basophilic, or chromophobic
atypical adenomas
elevated mitotic activity
nuclear p53 expression from TP53 mutations
more likely to behave aggressively, including invasion and recurrence
GNAS mutation in what
pituitary adenomas: except for GTL (gonadotrophs, lactotrophs, thyrotrophs)
galactorrhea and amenorrhea in females, sexual dysfunction, infertility
lactotroph adenoma
gigantism (children)
acromegaly (adults)
somatotroph adenoma
combined features of gH and prolcating excess
mammosomatotroph adenoma
cushing syndrome, nelson syndrome
corticotrohp adenoma
hyperthyroidism
thryotroph
hypogonadism, mass effects, and hypopituitarism
gonadotroph
other causes of hyperprolactinemia
-physiologic/normal
physiologic/normal
- pregancy
- nipple stimulation during suckling
- response to stress
other causes of hyperprolactinemia
-pathologic
lactotroph hyperplasia occurs when there is loss of dopamine mediated inhibition of prolactin
- damage of dopaminergic neurons of hypothal
- damage of pituitary stalk from head trauma
- drugs that block dopamine receptors on lactoroph cells
- any mass in suprasellar compartment may interfeere with inhibitory effect of hypothalamus on prolactin secretion
- renal failure
- hypothyroidism
treament for lactotroph adenoma
bromocriptine
surgery
somatoroph adenomas secrete GH which stimulates
hepatic secretion of IGF-1
acromegaly
after closure of epiphyses
- growth in skin and soft tissue
- viscera- thyroid, heart, liver, adrenals
- bones of face, hands, feet
- increased bone density
other findings with excess GH
gonadal dysfunction DM generalized muscle weakness hypertension arthritis CHF increased risk of GI cancer
diagnosis of excess GH
elevated GH and IGF-1
failure to suppress GH production in respons to an oral load of glucose
-very sensitive test for acromegaly
treatment for somatotroph adenoma
- surgery to remove
- somatostatin analogs (inhibit pituitary GH secretion)
- GH receptor antagnoist
corticotroph adenomas
secrete ACTH–> adrenal hypersecretion of cortisol–>hypercortisolism (cushing syndrome)
- usually microadenomas
- adenomas are PAS positive (PAS the weed in CA)
- carbs in POMC, the ACTH precursor molecule
- variable immunoreactivity for POMC and its derivatives, like ACTH and B-endorphin
cushing disease
when excessive production of ACTH by the pituitary called this
nelson syndrome
pt with preexisting corticotroph microadenoma
- occurs after surgical removal of adrenal glands for treatment of cushings syndrome
- loss of inhibiotor effect of adrenal corticosteroids
- large destructive pituitary adenoma with mass effect
- hyperpigmentation bc of ACTH precursor molecule on melanocyte
symptoms gonadotroph adenomas
most have mass effect
- impaired vision, HA, diplopia, pituitary apoplexy
- can get deficiency in LH = decreased energy and libido in men and amenorrhea in premenopausal women
nonfunctionaing pituitary adenoma can also cause what
can compress residual anterior pituitary causing hypopituitarism
- either slowly from enlargment
- abruptly from acute intratumoral hemorrhage (pituitary apoplexy)
pituitary carcinoma
rare
defined by metastases
most are functional and most commnly secrete prolacting and ACTH
if you have hypopituitarism and posterior pituitary dysfunction =
diabetes insipidus = hypothalamic origin
causes of hypopituitarism
tumors and other mass lesions
traumatic brain injury and subarachnoid hemorrhage
pituitary surgery or radiation
pituitary apoplexy (hemorrhage into pituitary gland, often occurin in pituitary adenoma, can cause death)
iscehmic necrosis of pituitary and sheehan syndrome
sheehan syndrome effects
anterior pituitary
posterior pituitary receives blood directly from arterial branches so less susceptible to injury
rathke cleft cyst can cause
hypopituitarism
hypothalamic lesions causing hypopituitarism
can also diminsh secretion of ADH–>DI
tumors: benign (craniopharyngioma) or maligant (metastases to the hypothalamus)
inflammatory disorders and infections causing hypopituitarism
sarcoidosis or tuberculous meningitis
primary empty sella
arachnoid mater and CSF herniate into sella and compress pituitary
seen in obese women with history of multiple pregnancies
pts have visual field defects, sometimes with hyperprolactinemia bc of interruption of inhibitory hypothalamic inputs
hypopituitarism GH deficiency
children can dvelop growth failure
hypopituitarism gonadotropin deficiency
amenorrhea and infertility in women
decreased libido, impotence, and loss of pubic and axillary hair in men
most frequent causes of SIADH
secretion of ADH by malignant neoplasms (particularly SCC of the lung)
drugs that increase ADH secretion
CNS disorders like infections and trauma
clinical manifestations of SIADH
hyponatremia, cerebral edema, and reultant neurologic dysfunction
most common suprasellar tumors and cause what
gliomas
craniopharyngiomas
cause hypo or hyper function of AP, DI or combinations
craniopharyngioma arise from what
age distribution
presentation
prognosis
remnants of rathkes pouch
bimodal age
- 1st peak is 5-15 yrs
- 2nd peak is at 65 and older
headaches and visual distrubances
children can have growth retardation due to pituitary hypofunction and GH deficiency
good prognosis
craniopharyngioma morphology
size is 3-4 cm in diameter
typically cystic, sometimes multiloculated (can be encapsulated)
often encroach on optic chiasm and CNs
can bulge into floor of third ventricle and base of brain
adamantinomatous craniopharyngioma
age
morphology
what rxn
children
calcified
nests of cords of stratified squamous epithelium with peripheral palisading and compact, lamerllar keratin
cyst formation: cholesterol-rich, thick brown-yellow fluid that is compared to “machine oil”
firbosis and chronic inflammation
extend little fingers of epithelium into adjacent brain–>brisk glial rxn
papillary craniopharyngioma
age
morphology
adults
rarely calcified
both solid sheets and papillae lined by well diff squamous epithelium
-no peripheral palisading
-usually lack keratin, calcification, and cysts
