Term
|
Definition
Smaller than 10 mm
Common; up to 40% incidence in autopsies
Usually solitary; if multiple, may be indistinguishable from nodular hyperplasia
Almost always confined to pituitary |
|
|
Term
|
Definition
Uncommon
10 mm or larger
May be confined to sella.
May erode bone in a seemingly invasive manner.
May obliterate the entire anterior lobe; sometimes the posterior lobe
described as "tulip shaped" by radiologists |
|
|
Term
|
Definition
causes: adenoma, drugs (eg estrogen therapy), pregnancy, nipple stimulation
The major effect is HYPGOGONADISM, BC THE HYPOTHYROID PRODUCES AN EXCESS DOPAMINE TO INHIBIT PROLACTIN SECRETION, BUT THE ADENOMA "KEEPS PUMPIN THAT SHIT"
Females: Galactorrhea,Amenorrhea (25% of cases)
Males:Impotence, Infertility |
|
|
Term
|
Definition
Most common pituitary tumor
30% of pituitary adenomas
May be small or large
Weakly acidophilic or chromophobic |
|
|
Term
|
Definition
| Can produce prolactin or growth hormone. |
|
|
Term
|
Definition
Gigantism is caused by
a somatotroph adenoma
functioning during physeal
growth.
Effect of accelerated
enchondral bone formation |
|
|
Term
|
Definition
Acromegaly is caused by a
somatotroph adenoma
functioning after skeletal
growth has ceased.
Bone length does not increase,
but increased periosteal bone
production leads to thickening.
Enlargement of hands, feet,
skull; increased joint space;
joint pain due to osteoarthrosis;
prognathism; insulin resistance,
glucose intolerance; airway
obstruction; hypertension;
cardiomyopathy. |
|
|
Term
|
Definition
| Cushing's Disease--adrenal hypersecretion |
|
|
Term
|
Definition
truncal obesity, hirsutism, "buffalo hump"
purple striae, muscle fatigue, hyperglycemia, immune dysfunction, calcium wasting? |
|
|
Term
|
Definition
Men may experience decreased libido related to decreased testosterone.
Premenopausal women may experience amenorrhea. |
|
|
Term
|
Definition
90% of cases are caused by destructive processes that directly involve the anterior pituitary.
Most common are nonsecretory adenomas, Sheehan’s syndrome, and empty sella syndrome.
Radiation, hemorrhage, infection, hypothalamic tumors also.
Clinical manifestations -
Hypofunction of target organs: gonads, adrenal, thyroid
Pituitary dwarfism in prepubertal children |
|
|
Term
|
Definition
can be due to hypopituitarism from a nonfunctioning basophilic tumor, a functioning prolactin tumor, drugs
Men
Testicular atrophy
Sterility
Loss of axillary and pubic hair
Women
Amenorrhea
Sterility
Loss of axillary and pubic hair
Atrophy of ovaries, external genitalia |
|
|
Term
| Common causes of Hypopituitarism |
|
Definition
Nonsecretory Chromophobe Adenoma
25 to 30% of pituitary tumors
Come to clinical attention because of
local effects
hypofunction of target organ
So-called “null-cell” adenomas
Sheehan’s Syndrome
Empty Sella Syndrome
Hypothalamic Suprasellar Tumors
Surgery, radiation, pituitary apoplexy |
|
|
Term
|
Definition
Primary
Defect in diaphragma sellae
Pituitary atrophy due to CSF pressure
Secondary
A mass, usually an adenoma, causes enlargement of the sella
It is subsequently ablated by surgery or radiation |
|
|
Term
|
Definition
Common cause of hypopituitarism
75% or more of the anterior lobe is destroyed suddenly by infarction
Pregnant women; anterior pituitary enlarges and compresses its blood vessels
Obstetric hemorrhage, hypotension, vasospasm, infarction
Hypogonadism, hypothyroidism, adrenal cortical insufficiency
Men, non-pregnant women also |
|
|
Term
| Hypothalamic Suprasellar Tumors |
|
Definition
Cause of hypogonadism/hypopituitarism
Craniopharyngiomas
Rathke’s pouch derived
aka adamantinoma, ameloblastoma
recapitulates enamel organ
squamous and/or glandular epithelium, fibrous stoma
Cystic or solid
papillary areas, bone, calcification may occur
present w/ headaches
histologically looks like tooth enamel |
|
|
Term
| Posterior Pituitary Syndromes |
|
Definition
| Dysfunction of the posterior pituitary results in ADH (arginine vasopressin) deficiency or Inappropriate secretion of ADH |
|
|
Term
| The most common cause of ADH deficiency |
|
Definition
| Metastatic carcinoma, from small cell carcinoma of the lung to the pituitary |
|
|
Term
| Inappropriate ADH secretion effects |
|
Definition
Persistent release of ADH results in
Inability to secrete a dilute urine
Excessive water resorption from glomerular filtrate expands the extracellular fluid volume and causes
Hyponatremia which may lead to
Cerebral edema, neurologic dysfunction |
|
|
Term
| Causes of Inappropriate ADH secretion |
|
Definition
Paraneoplastic secretion of ADH by
Small cell carcinoma of the lung
Other tumors
CNS hemorrhages, thromboses, infections
Pulmonary disorders
Pneumonia
Tuberculosis
Drugs |
|
|
Term
|
Definition
Tumors are virtually the only type of disorder to affect the pineal.
Germ cell tumors - 50 to 70%
Pinealomas make up the rest
Pinealoblastomas
Pineocytomas |
|
|
Term
|
Definition
Pinealoblastomas
Young patients
Small blue cells, neuroblastoma-like
Infiltrates locally; spreads via CSF
Survival beyond 1 or 2 years is rare
Pineocytomas
Adults mostly
Astrocytes or pineocytes, usually both
Slow-growing, not infiltrative
Complete removal usually impossible
Average survival 7 years |
|
|
