Pathology Ch. 24: Pituitary Gland

Front 1

What part of the pituitary is largest?

Back 1

Anterior pituitary

Front 2

How does the control of Prolactin release by the hypothalamus differ from all other hormones

Back 2

Its inhibitory: The release of dopamine from the hypothalamus inhibits Prolactin secretion

Front 3

What pituitary hormones stain acidophilic?

Back 3

Somatotrophs and lactotrophs. The others are basophilic

Front 4

What cells constitute half of all hormone-producing cells in the anterior pituitary?

Back 4

Somatotrophs

Front 5

Posterior pituitary consists of what type of cells?

Back 5

Modified glial cells called pituicytes and axonal processes/axon terminals.

Front 6

Where are the posterior pituitary hormones synthesized Where are they stored?

Back 6

Hypothalamus
In axon terminals of the post pituitary

Front 7

What causes oxytocin release during labor? What is its effect?

Back 7

Dilation of the cervix
Contraction of uterine smooth muscle

Front 8

What stimulates ADH release?

Back 8

Decreased blood pressure, sensed by baroreceptors in the cardiac atria and carotids
Increased osmotic pressure detected by osmoreceptors also triggers ADH secretion.

Front 9

Earliest changes referable to mass effect

Back 9

Radiagraphic abnormalities of the sella turcica

Front 10

How do nonfunctional pituitary adenomas present?

Back 10

Present with mass effects and hypopituitarism

Front 11

Mammosomatotroph adenoma

Back 11

Increased production of GH and Prolactin

Front 12

Associated symptoms gonadotroph adenoma

Back 12

Hypogonadism, mass effects, and hypopituitarism

Front 13

Most common cause of hyperpituitarism

Back 13

Adenoma of anterior lobe

Front 14

Functional adenoma
Non-functional adenoma

Back 14

Hormone excess and clinical manifestations thereof
Hormone excess w/o clinical presentation

Front 15

Silent and hormone-negative adenomas usually present when?

Back 15

At a later stage than those associated with endocrine abnormalities and are more likely to be macroadenomas

Front 16

Are the vast majority of incidentally diagnosed pituitary adenomas macro?

Back 16

No, they are usually found at autopsy as a microadenoma

Front 17

Best characterized molecular abnormality in pituitary adenoma. What mutation is present? What type of adenoma is usually present?

Back 17

Gain of function of mutation of the alpha-subunit (encoded by GNAS gene) of G-protein, Gsalpha. Caused by a dysfunction of intrinsic GTPase activity leading to continual activation of Gsalpha, persistent generation of cAMP and unchecked cellular proliferation.
GH adenoma

Front 18

A mutation of what enzyme is present with GH and prolactin adenomas

Back 18

Protein Kinase A

Front 19

A loss of function in what protein may lead to GH, Prolactin, and ACTH adenomas in MEN-1?

Back 19

Tumor-supressor protein MENIN

Front 20

The overwhelming majority of pituitary hormones arise this way

Back 20

They are sporadic and not genetic

Front 21

Aggressive adenomas are associated with gain of function of what gene? Loss of function of what gene leads to aggressive adenomas?

Back 21

Overexpression of Cyclin D1
Epigenetic silencing of Retinoblastoma gene (RB1)

Front 22

Invasive adenomas. What type of adenoma is more likely to be infiltrative? What is their clinical progression?

Back 22

Non-encapsulated, infiltrative tumors that invade the cavernous and sphenoid sinuses.
Macroadenoma
Foci of hemorrhage and necrosis

Front 23

Characteristic features that distinguish pituitary adenomas from non-neoplastic parenchyma

Back 23

Cellular monomorphism and the absence of reticulin meshwork

Front 24

Atypical Adenoma

Back 24

Mitotic activity with p53 mutations

Front 25

Histological characteristics of typical pituitary adenoma

Back 25

Unifrom, polygonal cells arrayed in sheets and cords. Supporting connective tissue and reticulin is absent, causing soft, gelatinous consistency. Mitotic activity is sparse.

Front 26

pituitary aploplexy

Back 26

Acute hemorrhage into an adenoma with rapid enlargement of the tumor

Front 27

Expanding pituitary tumors usually cause what symptoms?

Back 27

Abnormalities of sella turcica with mass effects
Bitemporal hemianopsia
Elevated ICP

Front 28

Most frequent type of hyperfunctioning pituitary adenoma. What different types are there?

Back 28

Prolactinoma:
Sparsely granulated: weakly acidophilic
Densely granulated: Strongly acidophilic (rare)

Front 29

Prolactinomas have a propensity to undergo what morphological change?

Back 29

Dystrophic calcification:
Ranging from psammoma bodies to extensive calcification

Front 30

Chracteristics of prolactin secretion from an adenoma

Back 30

Effecient and proportional

Front 31

Interference of normal dopamine secretion from the hypothalamus. How may this occur?

Back 31

Hyperprolactinemia w/ Lactotroph hyperplasia:
Can occur with damage to dopaminergic neurons and the pituitary stalk, or with dopamine inhibitors

Front 32

A mass where may cause prolactinemia in cases without a prolactinoma?

Back 32

Any mass in the suprasellar compartment may disturb the normal inhibitory influence of the hypothalamus on prolactin secretion

Front 33

Symtpoms of prolactinoma. Why is it easier to diagnose women? In men, does the adenoma advance to macro status?

Back 33

Prolactinemia, amenorrhea, galactorrhea, loss of libido, and infertility.
Loss of menstrual cycle
Yes

Front 34

When Somatotrophs come to clinical attention, what feature may they have?

Back 34

Because changes are subtle, they will be large

Front 35

Most bihormonal adenomas are what type? What histo feature do they have?

Back 35

Mammosomatotroph:
They are densely granulated

Front 36

What causes many of the clinical manifestations of GH adenoma?

Back 36

Elevated GH levels stimulate the hepatic secretion of IGF-1

Front 37

What determines Gigantism in children with elevated GH levels

Back 37

Whether the epiphyses have closed

Front 38

Sensitive test for acromegaly

Back 38

Failure to supress GH production in response to an oral load of glucose

Front 39

In acromegaly, growth of what tissues is most conspicuous? What viscera usually enlarge?

Back 39

Skin, soft tissues, viscera, and bones of the face, hands and feet
Thyroid, heart, liver, and adrenals

Front 40

Documentation of pituitary excess requires elevation of?

Back 40

GH and IGF1

Front 41

What drugs act to inhibit GH release?

Back 41

Somatostatins

Front 42

Typical presentation of non-functioning (silent) adenomas

Back 42

Mass Effects with compression of ant pituitary leading to hypopituitarism

Front 43

Demonstration of what is the sine qua non of pituitary carcinomas? What products are usually secreted?

Back 43

Craniospinal and systemic metastases
Prolactin and ACTH

Front 44

Excessive production of ACTH by the pituitary

Back 44

Cushings disease

Front 45

Large destructive pituitary adenoma developing after surgical removal of adrenal glands. Why do these occur? How do patients present?

Back 45

Neslon's disease:
These occur because of loss of inhibitory effect of adrenal corticosteroids on corticotroph adenoma.
Present with Mass Effects, instead of hypercortisolism

Front 46

How do ACTH adenomas usually stain?

Back 46

Densely granulated Basophilic w/ positive PAS due to presence of carbohydrate in POMC, the ATCH precursor

Front 47

Gonadotroph adenoma usually present how? What hormone is most likely deficient? What may this cause?

Back 47

Presents with neurological problems, such as impaired vision, headaches, diplopia, or pituitary apoplexy
LH is usually deficient
Decreased energy, libido, and hypogandism in men, with amenorrhea in women

Front 48

Hypopituitarism with Diabetes Insipidus is of what origin

Back 48

Hypothalamic

Front 49

Hypofunction of pituitary occurs when what % of the parenchyma is lost?

Back 49

75%

Front 50

Most common form of clinically significant ischemic necrosis of the anterior pituitary. When does this occur? Is the posterior pituitary affected?

Back 50

Sheehan syndrome:
During pregnency, the pituitary may double in size without an increase in blood supply, causing relative anoxia. Further reduction in size during obstetric hemorrhage or shock may lead to infarction of the anterior lobe.
The posterior pituitary is not affected because it receives its blood supply from arterial branches, and is not directly affected.

Front 51

Pt presents with excruciating headache, diplopia, and hypopituitarism

Back 51

Possibly pituitary apoplexy

Front 52

Most common cause of hypopituitarism

Back 52

Traumatic brain injury and subarachnoid injury

Front 53

Cysts that expand and compress the gland resulting in hypopituitarism. What epithelial lines these?

Back 53

Rathke cleft cysts:
Ciliated cuboidal epithelium with occasional goblet cells and anterior pituitary cells.

Front 54

Primary empty sella. What hormonal symptom may be secondary

Back 54

Defect in the diaphragmatic sella that allows the arachnoid mater and CSF to herniate into the sella and compress the pituitary gland, leading to hypopituitarism
Loss of inhibition of prolactin from the hypothalamus, leads to prolactinemia.

Front 55

End result of Sheehan syndrome

Back 55

Fibrosis of pituitary gland

Front 56

Secondary empty sella

Back 56

A mass or tumor enlarges the sella, but is surgically removed, or killed, leading to spontaneous hypofunction.

Front 57

ADH deficiency is characterized by? Clinical manifestations?

Back 57

Excessive urinary excretion, causing Diabetes Insipidus.
Low specific gravity and increased serum Na and osmolality, resulting in thirst and polydipsia

Front 58

Resorption of excess amounts of free water is from? What does this cause? Does peripheral edema develop?

Back 58

SIADH:
Excess ADH secretion causing hyponatremia, cerebral edema, and neurologic dysfunction
No, The total body water increases, but blood volume remains normal, and peripheral edema does not develop.

Front 59

Most likely cause of SIADH

Back 59

Ectopic secretion of ADH by malignant neoplasms (particularly small-cell carcinoma). Drugs that increase ADH secretion, or and CNS disorders.

Front 60

What type of tumors may cause hyper- or hypopituitarism?

Back 60

Hypothalamic suprasellar tumors

Front 61

Abnormalities of what signaling pathway has been implicated in craniopharyngiomas

Back 61

WNT