Pathology of the Pituitary

Question 1

most susceptible part of the pitutitary

Answer 1

infundibulum (stalk)

Question 2

two negative feedbacks in the pituitary

Answer 2

doapine –> - PRL

somatostain –> - GH

Question 3

Somatotrophs,

Answer 3

producing growth hormone (GH)

Question 4

Mammosomatotrophs,

Answer 4

producing GH and prolactin (PRL)

Question 5

Lactotrophs,

Answer 5

producing PRL

Question 6

Corticotrophs

Answer 6

producing adrenocorticotropic hormone (ACTH) and pro-opiomelanocortin (POMC), melanocyte-stimulating hormone (MSH)

Question 7

Thyrotrophs,

Answer 7

, producing thyroid-stimulating hormone (TSH),

Question 8

Gonadotrophs

Answer 8

producing follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

Question 9

normal pituitary stains

Answer 9

heterogeneously

lost of different stuff

Question 10

bitemporal hemianopia

Answer 10

from pituitary tumor compressing optic chiasm

Question 11

how does cerebral edema present?

Answer 11

vomiting
headaches

look in eye- optic cup widened = papilledema

Question 12

female complaining of leaky nipples, new onset headaches, serum prolactin elevated

Answer 12

pituitary adenoma

Question 13

The most common cause of hyperpituitarism

Answer 13

is an adenoma arising in the anterior lobe

Question 14

pituitary adenomas usually found what age?

Answer 14

adults, peak 25-50 years

Question 15

microadenomas vs macroadenomas

Answer 15

micro less than 1 cm, likely to be functional

; macro is greater than 1 cm, likely to be nonfunctional

Question 16

pituitary monomorphism

Answer 16

probably a prolactin adenoma

reticulin stain would normally show a network in the pituitary, but in adenoma it’s missing

Question 17

dense core granules in MRI indicate

Answer 17

neuroendocrine

Question 18

Clinical course of pituitary adenoma

Answer 18

The signs and symptoms of pituitary adenomas are related to endocrine abnormalities and mass effects. Local mass effects may be produced by any type of pituitary tumor.

these effects include radiographic abnormalities of the sella turcica, visual field abnormalities, signs and symptoms of elevated intracranial pressure, and occasionally hypopituitarism.

Acute hemorrhage into an adenoma is sometimes associated with pituitary apoplexy

Question 19

Increased serum levels of prolactin cause

Answer 19

amenorrhea, galactorrhea, loss of libido, and infertility.

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 sensitivity of menses to disruption by hyperprolactinemia.

Question 20

Lactotroph adenoma

Answer 20

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

Question 21

Somatotroph Adenomas

Answer 21

Growth hormone (GH)-secreting somatotroph adenomas are the second most common type of functioning pituitary adenoma, and cause * gigantism in children and acromegaly in adults (epyphyses are closed). Somatotroph adenomas may be quite large by the time they come to clinical attention because the manifestations of excessive GH may be subtle.

Question 22

Clinical course of somatotroph adenomas

Answer 22

Persistently elevated levels of GH stimulate the hepatic secretion of insulin-like growth factor 1 (IGF-1), which causes many of the clinical manifestations.

Question 23

If a somatotroph adenoma appears in children before the epiphyses have closed,

Answer 23

the elevated levels of GH (and IGF-1) result in gigantism. This is characterized by a generalized increase in body size with disproportionately long arms and legs.

Question 24

If a somatotroph adenoma increased levels of GH are present after closure of the epiphyses,

Answer 24

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

Question 25

Growth hormone excess can also cause

Answer 25

Bone density may increase (hyperostosis) in both the spine and the hips. Enlargement of the jaw results in its protrusion (prognathism), and broadening of the lower face. The feet and hands are enlarged, and the fingers become thickened and sausage-like. In most instances gigantism is also accompanied by evidence of acromegaly. These changes may develop slowly over decades before being recognized, hence the opportunity for the adenomas to reach substantial size. GH excess can also be associated with a variety of other disturbances, including gonadal dysfunction, diabetes mellitus, generalized muscle weakness, hypertension, arthritis, congestive heart failure, and an increased risk of gastrointestinal cancers.

Question 26

The diagnosis of pituitary GH excess relies on

Answer 26

documentation of elevated serum GH and IGF-1 levels. In addition, *** failure to suppress GH production in response to an oral load of glucose is one of the most sensitive tests for acromegaly.

Question 27

Corticotroph Adenomas

Answer 27

Excess production of ACTH by functioning corticotroph adenomas leads to adrenal hypersecretion of cortisol and the development of hypercortisolism (also known as Cushing syndrome).

Question 28

Cushing disease.

Answer 28

When the hypercortisolism is due to excessive production of ACTH by the pituitary, it is designated Cushing disease.

Question 29

Nelson syndrome

Answer 29

Large destructive pituitary adenomas can develop in patients after surgical removal of the adrenal glands for treatment of Cushing syndrome. This condition, known as Nelson syndrome, 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, and patients present with mass effects due to the pituitary tumor, and there can be hyperpigmentation because of the stimulatory effect of other products of the ACTH precursor molecule on melanocytes

Question 30

Gonadotroph adenomas

Answer 30

(LH-producing and FSH-producing) adenomas can be difficult to recognize because they secrete hormones inefficiently and variably, and the secretory products usually do not cause a recognizable clinical syndrome (nonfunctioning adenomas). Gonadotroph adenomas 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.

Question 31

Pituitary hormone deficiencies

Answer 31

most commonly impaired secretion of LH. This causes decreased energy and libido in men (due to reduced testosterone) and amenorrhea in premenopausal women. 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.

Question 32

Thyrotroph (TSH-producing) adenomas

Answer 32

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

Question 33

Nonfunctioning pituitary adenomas

Answer 33

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, nonfunctioning adenomas typically present with symptoms stemming from mass effects. These lesions may also compromise the residual anterior pituitary sufficiently to cause hypopituitarism, which may appear slowly due to gradual enlargement of the adenoma or abruptly because of acute intratumoral hemorrhage (pituitary apoplexy).

Question 34

Robbins Key Concepts: hyperpituitarism

Answer 34

most common cause- anterior lobe pituitary adenoma can be macro or micro (less than 1 cm) functioning- associated with endo signs and symptoms. Nonfunctioning- mass effects, including visual disturbances lactotroph adenomas- amenorrhea, galactorrhea, loss of libido, infertility somatotroph adenomas- gigantism in kids, acromegaly in adults, impaired glucose tolerance, diabetes mellitus corticotroph adenomas- cushing syndrome and hyperpigmentation distinctive morphologic features of most adenomas: cellular monomorphis and absence of reticulin network

Question 35

25-year-old male sustains a IED explosion and survives with multiple medical problems He complains of being tired He notices a loss of libido, impotence, and loss of pubic and axillary hair

Answer 35

hypopituitarism TSH, FSH, LH, and MSH decreased brain shaking can beat up the stalk

Question 36

Hypopituitarism

Answer 36

refers to decreased secretion of pituitary hormones, which can result from diseases of the hypothalamus or of the pituitary Most cases of hypopituitarism arise from destructive processes directly involving the anterior pituitary.

Question 37

Differential diagnosis of hypopituitarism

Answer 37

Tumors and other mass lesions *** Traumatic brain injury and subarachnoid hemorrhage are among the most common causes of pituitary hypofunction Pituitary surgery or radiation Pituitary apoplexy Ischemic necrosis of the pituitary and Sheehan syndrome Rathke cleft cyst Empty sella syndrome Hypothalamic lesions Inflammatory disorders and infections Genetic defects

Question 38

Clinical manifestations of hypopituitarism

Answer 38

Children can develop growth failure (pituitary dwarfism) due to growth hormone deficiency. Gonadotropin (LH and FSH) deficiency leads to amenorrhea and infertility in women and decreased libido, impotence, and loss of pubic and axillary hair in men. TSH and ACTH deficiencies result in symptoms of hypothyroidism and hypoadrenalism, respectively. Prolactin deficiency results in failure of postpartum lactation. The anterior pituitary is also a rich source of MSH, synthesized from the same precursor molecule that produces ACTH; therefore, one of the manifestations of hypopituitarism includes pallor due to a loss of stimulatory effects of MSH on melanocytes.

Question 39

Posterior Pituitary Syndromes

Answer 39

diabetes insipidus and SIADH

Question 40

Diabetes insipidus

Answer 40

ADH deficiency causes diabetes insipidus, a condition characterized by excessive urination (polyuria) due to an inability of the kidney to resorb water properly from the urine

Question 41

Syndrome of inappropriate ADH (SIADH) secretion

Answer 41

ADH excess causes resorption of excessive amounts of free water, resulting in hyponatremia

Question 42

52-year-old male presents with confusion and headache 20+ years smoker, chest x-ray performed hyponatremia

Answer 42

SIADH

Question 43

23-year-old male suffered head trauma secondary to motor vehicle accident On exam is mildly confused but oriented times three hypernatremia BUN and creatinine elevated

Answer 43

diabetes insipidus

Question 44

Diagnosis of diabetes insipidus

Answer 44

Diabetes insipidus. ADH deficiency causes diabetes insipidus, a condition characterized by excessive urination (polyuria) due to an inability of the kidney to resorb water properly from the urine.

Question 45

central vs nephrogenic diabetes insipidus

Answer 45

Diabetes insipidus from ADH deficiency is designated as central to differentiate it from nephrogenic diabetes insipidus, which is a result of renal tubular unresponsiveness to circulating ADH. The clinical manifestations of these two disorders are similar and include the excretion of large volumes of dilute urine with a lower than normal specific gravity. Serum sodium and osmolality are increased by the excessive renal loss of free water, resulting in thirst and polydipsia.

Question 46

normal shape of lateral ventricles

Answer 46

V shape

Question 47

Hypothalamic Suprasellar Tumors

Answer 47

Neoplasms in this location may induce hypofunction or hyperfunction of the anterior pituitary, diabetes insipidus, or combinations of these manifestations. The most commonly implicated tumors are gliomas and craniopharyngiomas. A bimodal age distribution is observed, with one peak in childhood (5 to 15 years) and a second peak in adults 65 years or older. Patients usually come to attention because of headaches and visual disturbances, while children sometimes present with growth retardation due to pituitary hypofunction and GH deficiency

Question 48

The craniopharyngioma is thought to arise from

Answer 48

vestigial remnants of Rathke pouch. These slow-growing tumors account for 1% to 5% of intracranial tumors.

Question 49

morphology of craniopharyngiomas

Answer 49

average 3-4 cm, 2 types: adamantinomatous (kids)- frequently have calcifications papillary (more in adults)- less frequent calcifications

Question 50

prognosis with craniopharyngiomas and frequent findings

Answer 50

excellent recurrence-free and overall survival. crankcase oil and calcifications