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2H. Pathology > Endoc- Pituitatry- Clin Manifestations > Flashcards

Endoc- Pituitatry- Clin Manifestations Flashcards

1
Q

The manifestations of pituitary disorders are as follows:

A
  1. Hyperpituitarism
  2. Hypopituitarism
  3. Local mass effects
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2
Q

_____________

Arising from excess secretion of trophic hormones.

A

Hyperpituitarism:

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3
Q

The causes of
hyperpituitarism include

A
  1. pituitary adenoma,
  2. hyperplasia and carcinomas of the anterior

pituitary,

  1. secretion of hormones by nonpituitary tumors, and
  2. certain hypothalamic
    disorders.
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4
Q

: Arising from deficiency of trophic hormones.

This may be caused by
destructive processes, including ischemic injury, surgery or radiation, inflammatory
reactions, and nonfunctional pituitary adenomas

A

Hypopituitarism

” Nmemonics: NADESTROY so cant produce!!!” Anything that destructs the gland HYPO!

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5
Q

Local mass effects: Among the earliest changes referable to mass effect are radiographic abnormalities of the sella turcica,

A

including sellar expansion,

bony erosion,

and disruption of the diaphragma sella.

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6
Q

Because of the close proximity of the optic nerves and chiasm to the sella, expanding pituitary lesions often compress decussating fibers in the optic chiasm. This gives rise to visual field abnormalities , classically in the form of defects in the lateral (temporal) visual fields, so-called _______________

A

bitemporal hemianopsia

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7
Q

. In addition, a variety of other visual field abnormalities may be caused by asymmetric growth of many tumors. Like any expanding intracranial mass, pituitary adenomas can produce signs and symptoms of elevated intracranial pressure , including headache, nausea, and vomiting.

A
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8
Q

The most common cause of hyperpituitarism is an ___________arising in the anterior lobe.

A

adenoma

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9
Q

Pituitary adenomas are classified on the basis of hormone(s) produced by the neoplastic cells,
which are detected by immunohistochemical stains

A
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10
Q

Some pituitary adenomas
can secrete two hormones (___________ being the most common combination), and rarely,
pituitary adenomas are plurihormonal.

A

GH and prolactin

Nmemonics: GP General Physician

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11
Q

Pituitary adenomas can be_________i.e., associated
with hormone excess and clinical manifestations thereof) or ______________ (i.e.,
immunohistochemical and/or ultrastructural demonstration of hormone production at the tissue
level, without clinical symptoms of hormone excess).

A
  1. Functional
  2. nonfunctional
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12
Q

Less common causes of hyperpituitarism
include ____________- and some hypothalamic disorders.

TABLE 24-1 – Classification of Pituitary Adenomas

A

pituitary carcinomas

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13
Q

Large pituitary adenomas, and
particularly nonfunctioning ones, may cause ___________ as they encroach on and destroy
adjacent anterior pituitary parenchyma.

A

hypopituitarism

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14
Q

TABLE 24-2 – Genetic Alterations in Pituitary Tumors

gene: Gsα

Activating mutation

A

GH adenomas

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15
Q

TABLE 24-2 – Genetic Alterations in Pituitary Tumors

GAIN OF FUNCTION

LOSS OF FUNCTION

A
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16
Q

What are the genes that cause

GAIN OF FUNCTION?

A
  1. Gsα
  2. Protein kinase A (PKA)
  3. Cyclin D1
  4. HRAS
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17
Q

Protein kinase A (PKA)

Germline inactivating mutations of PRKARIA
(Carney complex), a negative regulator of PKA

A

GH and prolactin
adenomas

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18
Q

Cyclin D1

Overexpression

A

Aggressive
adenomas

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19
Q

HRAS

Activating mutation

A

Pituitary
carcinomas

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20
Q

LOSS OF FUNCTION

A
  1. Menin
  2. CDKN1B (p27/KIP1)
  3. Aryl hydrocarbon receptor
    interacting protein (AIP)
  4. Retinoblastoma (RB)
    protein
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21
Q

Menin [*]

Germline inactivating mutations of MEN1
(multiple endocrine neoplasia, type 1)

A

GH, prolactin, and
ACTH adenomas

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22
Q

*****CDKN1B (p27/KIP1) [*]

Germline inactivating mutations of CDKN1B
(“MEN-1-like” syndrome)

A

ACTH adenomas

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23
Q

****Aryl hydrocarbon receptor interacting protein (AIP) [*]

Germline mutations of AIP (pituitary adenoma
predisposition [PAP] syndrome)

A

GH adenomas

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24
Q

Retinoblastoma (RB)
protein
Methylation of RB gene promoter

A

Aggressive
adenomas

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25
Q

Genetic alterations associated with familial predisposition to pituitary adenomas.

A

Protein kinase A (PKA) [*]

Menin

CDKN1B (p27/KIP1) [*]

Aryl hydrocarbon receptor
interacting protein (AIP) [\*]
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26
Q

Morphology.

The typical pituitary adenoma is a_________________.

A

soft, well-circumscribed lesion that may be confined to the sella turcica

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27
Q

Larger lesions typically extend superiorly through the diaphragm sella into the suprasellar region, where they often compress the optic chiasm and adjacent structures, such as some of the cranial nerves ( Fig. 24-4 ). As these adenomas expand, they frequently erode the sella turcica and anterior clinoid processes.

In as many as 30% of cases, the adenomas are not grossly encapsulated and infiltrate neighboring tissues such as the cavernous and sphenoid sinuses, dura, and on occasion, the brain itself. Such lesions are termed____________.

A

invasive adenoma

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28
Q

Not unexpectedly, ____________tend to be invasive more
frequently than smaller tumors.

Foci of hemorrhage and necrosis are also more common in
these larger adenomas.

A

**macroadenomas **

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29
Q

Histologically, typical pituitary adenomas are composed of relatively___________________-.

A
  • uniform, polygonal cells arrayed in sheets or cords
  • Supporting connective tissue, or reticulin, is sparse,
    • ​accounting for the soft, gelatinous consistency of many of these lesions.
  • Mitotic activity is usually sparse.
  • The cytoplasm of the constituent cells may be acidophilic, basophilic, or chromophobic, depending on the type and amount of secretory product within the cells, but it is generally uniform throughout the tumor.
30
Q

​What is the reason in accounting for the** soft, gelatinous consistency of many of these lesions** in pituitary adenomas?

A

Supporting connective tissue, or reticulin, is sparse,

31
Q

*****What distinguish pituitary adenomas from non-neoplastic anterior pituitary parenchyma?

A

This cellular monomorphism and the absence of a significant reticulin network distinguish pituitary adenomas from non-neoplastic anterior pituitary parenchyma ( Fig. 24-5 ).

32
Q

The biologic behavior of the adenoma cannot always be reliably predicted from its histologic appearance. T or F

A

T

33
Q

A subset of pituitary adenomas demonstrates brisk mitotic activity and staining of greater than 3% of the nuclei with the proliferation marker Ki-67; these tumors typically also demonstrate extensive nuclear p53 immunoreactivity in the neoplastic cells, a feature that correlates with the presence of p53 mutations. It is recommended that adenomas with this profile be classified as ______________, since these tumors have a higher propensity for aggressive behavior, including invasion and recurrence.

A

atypical adenomas

34
Q

Clinical Course.

The signs and symptoms of pituitary adenomas include endocrine abnormalities and mass effects.

The effects of excessive secretion of anterior pituitary hormones are mentioned below, when the specific types of pituitary adenoma are described.

Local mass effects may be encountered in any type of pituitary tumor and have been discussed previously under clinical
manifestations of pituitary disease.

Briefly, these include________________________________.

Acute hemorrhage into an adenoma is sometimes associated with pituitary apoplexy , as was noted above.
With this general introduction to pituitary adenomas, we proceed to a discussion of the individual types of tumors.

A
  1. radiographic abnormalities of the sella turcica,
  2. visual field abnormalities,
  3. ** signs and symptoms of elevated intracranial pressure,**
  4. **and occasionally hypopituitarism. **
35
Q

PROLACTINOMAS
______________________ are the most frequent type of hyperfunctioning pituitary
adenoma, accounting for about 30% of all clinically recognized cases.

These lesions range from
small microadenomas to large, expansile tumors associated with substantial mass effect.

A

PROLACTINOMAS

Prolactinomas (lactotroph adenomas

36
Q

Microscopically, the overwhelming majority of prolactinomas are composed of ________________ ;

A

weakly acidophilic
or chromophobic cells (sparsely granulated prolactinoma

37
Q

rare prolactinomas are
________________________ ( Fig. 24-6 ).

A

strongly acidophilic (densely granulated prolactinoma)

38
Q

Prolactin can be demonstrated within the secretory granules in the cytoplasm of the cells using immunohistochemical stains.

Prolactinomas have a propensity to undergo dystrophic calcification, ranging from___________________
Prolactin secretion by functioning adenomas is usually efficient (even microadenomas secrete
sufficient prolactin to cause hyperprolactinemia) and proportional, in that serum prolactin
concentrations tend to correlate with the size of the adenoma

A

** isolated psammoma bodies** to extensive calcification of virtually the** entire tumor mass (“pituitary stone”).**

39
Q

Increased serum levels of prolactin, or prolactinemia, cause __________________________.

A

amenorrhea,

galactorrhea,

loss of libido,

and infertility

40
Q

The diagnosis of an adenoma is made more readily in women than in men, especially between the ages of 20 and 40 years, presumably **because of the_______________ **

Prolactinoma underlies almost a quarter of cases of amenorrhea. In contrast, in men and older women, the hormonal manifestations may be subtle, allowing the tumors to reach considerable size (macroadenomas) before being detected clinically.

A

** sensitivity of menses to disruption by hyperprolactinemia.**

41
Q

Hyperprolactinemia may result from causes other than prolactin-secreting pituitary adenomas .

Physiologic hyperprolactinemia occurs in _____________

.

A
  1. pregnancy;
  2. serum prolactin levels increase throughout pregnancy, reaching a peak at delivery.
  3. Prolactin levels are also elevated by nipple stimulation, as occurs during suckling in lactating women,
  4. and as a response to many types of stress
42
Q

Pathologic hyperprolactinemia can also result from** **

A
  1. lactotroph hyperplasia, such as when there is** interference with normal dopamine inhibition of prolactin secretion**.
    • ​​This may occur as a result of damage to the dopaminergic neurons of the hypothalamus, damage to the pituitary stalk (e.g., due to head trauma), or **drugs that block dopamine receptors on lactotroph cells. **
  2. ​Any mass in the suprasellar compartment may disturb the normal inhibitory influence of the hypothalamus on prolactin secretion, resulting in hyperprolactinemia. *****Therefore, a mild elevation in serum prolactin in a person with a pituitary adenoma does not necessarily indicate a prolactin-secreting tumor.
  3. **Other causes of hyperprolactinemia include several classes of drugs (such as dopamine antagonists), estrogens, renal failure, and hypothyroidism. **
43
Q

How is prolactinomas treated?

A

Prolactinomas are treated by surgery or, more commonly, with bromocriptine, a dopamine receptor agonist that causes the lesions to diminish in size.

44
Q

_________________ are the second most common type of functioning pituitary adenoma.

A

GH-secreting tumors

45
Q

Somatotroph cell adenomas may be quite large by the time they come to clinical attention because______________.

A

the manifestations of excessive GH may be subtle

46
Q

Histologically, pure GH cell –containing adenomas are also classified into two subtypes:

A
  1. densely granulated and
  2. sparsely granulated.
47
Q

The densely granulated adenomas are composed of cells that are _____________in routine sections, retain strong cytoplasmic GH reactivity on immunohistochemistry, and demonstrate cytokeratin staining in a perinuclear distribution.

A

monomorphic and acidophilic

48
Q

In contrast, the sparsely granulated variants are composed of ____________________________

A

chromophobe cells with considerable nuclear and cytologic pleomorphism and focal, weak staining for GH.

49
Q

Bihormonal mammosomatotroph adenomas that express both GH and prolactin are being increasingly recognized with the availability of better immunohistochemical reagents; morphologically, most bihormonal adenomas resemble the _____________________

A

densely granulated pure somatotroph adenomas.

50
Q

Persistently elevated levels of GH stimulate the hepatic secretion of _________________, which causes many of the clinical manifestations.

A

insulin-like growth factor 1 (IGF-1 or somatomedin C)

51
Q

If a somatotrophic adenoma appears in children before the epiphyses have closed, the elevated levels of GH (and IGF-1) result in____________

This is characterized by a generalized increase in body size with disproportionately long arms and legs.

A

** gigantism**.

52
Q

If the increased levels of GH are present after closure of the epiphyses, patients develop ________.

In this condition, growth is most conspicuous in skin and soft tissues; viscera (thyroid, heart, liver, and adrenals); and bones of the face, hands, and feet.

Bone density may be increased (hyperostosis) in both the spine and the hips.

Enlargement of the jaw results in protrusion (prognathism), with broadening of the lower face.

The hands and feet are enlarged with broad, sausage-like fingers.

In most instances gigantism is also accompanied by evidence of acromegaly. These changes develop for decades before being recognized, hence the opportunity for the adenomas to reach substantial size**. **

A

acromegaly

53
Q

GH excess is also correlated with a variety of other disturbances, including

A
  1. gonadal dysfunction,
  2. diabetes mellitus,
  3. generalized muscle weakness,
  4. hypertension, arthritis,
  5. congestive heart failure, an
  6. an increased risk of gastrointestinal cancers.
54
Q

The diagnosis of pituitary GH excess relies on documentation of________________.

A

** elevated** serum GH and IGF-1 levels

55
Q

In addition,____________ is one of the most sensitive tests for acromegaly.

A

failure to suppress GH production in response to an oral load of glucose

56
Q

What is the treatment pituitary adenoma?

A

The underlying pituitary adenoma can be either removed surgically or treated via pharmacologic means.

The latter includes somatostatin analogs (recall that somatostatin has an inhibitory effect on pituitary GH secretion) or the use of GH receptor antagonists, which prevent hormone binding to target organs such as the liver.

When effective control of high GH levels is achieved, the characteristic tissue overgrowth and related symptoms gradually recede, and the metabolic abnormalities improve.

57
Q

_____________ are usually small microadenomas at the time of diagnosis. These tumors are most often basophilic (densely granulated) and occasionally chromophobic (sparsely granulated). Both variants stain positively with periodic acid–Schiff (PAS) because of the presence of carbohydrate in POMC, the ACTH precursor molecule; in addition, they demonstrate variable immunoreactivity for POMC and its derivatives, including ACTH and β- endorphin.

A

Corticotroph adenomas

58
Q

Excess production of ACTH by the corticotroph adenoma leads to _________________and the _______________.

This syndrome is discussed in more detail later with the diseases of the adrenal gland.

It can be caused by a wide variety of conditions in addition to ACTH-producing pituitary tumors.

A

adrenal hypersecretion of cortisol

development of hypercortisolism (also known as** Cushing syndrome).**

59
Q

When the hypercortisolism is due to excessive production of ACTH by the pituitary, the process is designated ______________

A

Cushing disease.

60
Q

Large destructive adenomas can develop in patients after surgical removal of the adrenal glands for treatment of Cushing syndrome. This condition, known as_____________-occurs most often because of a loss of the inhibitory effect of adrenal corticosteroids on a preexisting corticotroph microadenoma.

Because the adrenals are absent in persons with this disorder, hypercortisolism does not develop.

In contrast, patients present with mass effects of the pituitary tumor. In addition, there can be hyperpigmentation because of the stimulatory effect of other products of the ACTH precursor molecule on melanocytes.

A

Nelson syndrome,

61
Q

OTHER ANTERIOR PITUITARY ADENOMAS

A
  1. Gonadotroph (LH-producing and FSH-producing) adenomas
  2. Thyrotroph (TSH-producing) adenomas
  3. Nonfunctioning pituitary adenomas
  4. Pituitary carcinomas
62
Q

Pituitary adenomas may elaborate more than one hormone. For example, prolactin may be
demonstrable by immunolabeling of somatotroph adenomas. In other cases, unusual
plurihormonal adenomas are capable of secreting multiple hormones; these tumors are usually
aggressive. A few comments are made about several of the less frequent functioning tumors.

A
63
Q

_________________can be difficult to recognize because they secrete hormones inefficiently and variably, and the secretory products usually do not cause a recognizable clinical syndrome (non-functioning adenomas, see below).

  • are most frequently found in middle-aged men and women when they become large enough to cause neurologic symptoms, such as impaired vision, headaches, diplopia, or pituitary apoplexy.
A

Gonadotroph (LH-producing and FSH-producing) adenomas

64
Q

In Gonadotroph ,Pituitary hormone deficiencies can also be found, most commonly impaired secretion of ___________.

This causes decreased energy and libido in men (due to reduced testosterone) and amenorrhea in premenopausal women.

A

LH.

65
Q

Thus, gonadotroph adenomas are paradoxically associated with _______________

. The neoplastic cells usually demonstrate immunoreactivity for the common gonadotropin α-subunit and the specific β-FSH and β-LH subunits; FSH is usually the predominant secreted hormone.

A

secondary gonadal hypofunction

66
Q

______________ are rare, accounting for approximately 1% of all
pituitary adenomas. Thyrotroph adenomas are a rare cause of hyperthyroidism.

A

Thyrotroph (TSH-producing) adenomas

67
Q

_______________are a heterogeneous group that constitutes approximately 25% to 30% of all pituitary tumors.

Their lineage can be established by immunohistochemical staining for hormones or by biochemical demonstration of cell type-specific transcription factors.

In the past, many such tumors have been called silent variants or null-cell adenomas.

Not surprisingly, the typical presentation of nonfunctioning adenomas is mass effects.

These lesions may also compromise the residual anterior pituitary sufficiently to cause hypopituitarism.

This may occur as a result of gradual enlargement of the adenoma or after abrupt enlargement of the tumor because of acute hemorrhage (pituitary apoplexy).

A

Nonfunctioning pituitary adenomas

68
Q

____________ are quite rare, accounting for less than 1% of pituitary tumors.

A

Pituitary carcinomas

69
Q

The demonstration of _______________ is a sine qua non of a pituitary carcinoma.

A

craniospinal or systemic metastases

70
Q

The majority of pituitary carcinomas are functional neoplasms, with prolactin and
ACTH being the most common secreted products. Metastases usually appear late in the
course, following multiple local recurrences

A

functional neoplasms, with prolactin and
ACTH

71
Q
A

2H. Pathology (49 decks)

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