Pathology 1: Pituitary Diseases

Question 1

List the 2 components of the pituitary gland?

Answer 1

1- Anterior (adenohypophysis) 80%.
2- Posterior (neurohypophysis).

Question 2

List the 5 pituitary cell types?

Answer 2

1- Somatotrophs.
2- Lactotrophs (mammosomatotrophs).
3- Corticotrophs.
4- Thyrotrophs.
5- Gondatrophs.

Question 3

Which hormone is produced by somatotrophs, what is its cytoplasm characteristics, and associated syndrome?

Answer 3

Hormone: GH.
Cytoplasm characteristics: acidophilic cells (eosinophilic cytoplasm).
Associated syndrome: gigantism (children), acromegaly (adults).

Question 4

Which hormone is produced by lactotrophs (mammosomatotrophs), what is its cytoplasm characteristics, and associated syndrome?

Answer 4

Hormone: prolactin, GH.
Cytoplasm characteristics: acidophilic cells.
Associated syndrome: galactorrhea and amenorrhea (females), sexual dysfunction and infertility (males).

Question 5

Which hormone is produced by corticotrophs, what is its cytoplasm characteristics, and associated syndrome?

Answer 5

Hormone: ACTH, MSH, POMC.
Cytoplasm characteristics: basophilic cells (basophil cytoplasm).
Associated syndrome: Cushing syndrome, Nelson syndrome.

Question 6

Which hormone is produced by thyrotrophs, what is its cytoplasm characteristics, and associated syndrome?

Answer 6

Hormone: TSH.
Cytoplasm characteristics: pale basophilic cells.
Associated syndrome: hyperthyroidism.

Question 7

Which hormone is produced by goandotrophs, what is its cytoplasm characteristics, and associated syndrome?

Answer 7

Hormone: FSH, LH.
Cytoplasm characteristics: basophilic cells.
Associated syndrome: hypogonadism, mass effects, hypopituitarism.

Question 8

What is the posterior pituitary gland?

Answer 8

Modified glial cells extending from hypothalamus (axon terminals).

Question 9

What are the 2 hormones secreted by the posterior pituitary gland?

Answer 9

1- oxytocin (contraction of uterine and lactiferous ducts smooth muscle).
2- ADH/vasopressin (water retention).

Question 10

What is the histology of adenohypophysis?

Answer 10

• Pink acidophils > GH, PRL.
• Dark purple basophils > ACTH, TSH, FSH, LH.
• Pale staining chromophobes > few cytoplasmic granules may have secretory activity.

Question 11

What is the histology of neurohypophysis?

Answer 11

Resembles neural tissue.
(Glial cells, nerve fibers, nerve endings, and intra-axonal neurosecretory granules).

Question 12

List 3 pituitary gland diseases?

Answer 12

1- Hyperpituitarism.
2- Hypopituitarism.
3- Local mass effect.

Question 13

List the clinical manifestations of Hyperpituitarism?

Answer 13

Adenomas, hyperplasia, carcinoma of anterior pituitary, secretion of hormones by some extra-pituitary tumors.

Question 14

List the clinical manifestations of Hypopituitarism?

Answer 14

Ischemic injury, surgery, radiation, inflammation.

Question 15

What are pituitary adenomas classified on the basis of?

Answer 15

On the basis of hormone produced by the neoplastic cells.

Question 16

Pituitary adenomas can be ________ or _________.

Answer 16

Functional or silent.

Question 17

What are pituitary adenomas composed of?

Answer 17

Both functional and silent pituitary adenomas are composed of a single cell type and produce a single hormone.

They may also be hormone negative (Null cell).

Question 18

Which type of pituitary adenoma is more likely to be macroadenomas?

Answer 18

Silent and hormone-negative adenomas.

Question 19

What is the difference between microadenomas and macroadenomas?

Answer 19

Microadenomas <1 cm.
Macroadenomas >1 cm.

Question 20

Mass effect of adenoma may cause which complication?

Answer 20

May compress the fibers of optic chiasm causing bitemoporal hemianopsia.

Question 21

What is the morphology of pituitary adenoma?

Answer 21

A well-circumscribed, soft lesion.

Question 22

What is the difference in morphology of small vs. large pituitary adenomas?

Answer 22

Small tumors is confined by the sella turcica.
Large lesions extend superiorly into the suprasellar region.

Question 23

30% of pituitary adenomas are which type?

Answer 23

Invasive adenomas.

Question 24

What is the morphology of invasive adenomas?

Answer 24

Non-encapsulated and infiltrate bone, dura, and brain.

Question 25

Foci of hemorrhage and/or necrosis are common in which type of pituitary adenomas?

Answer 25

Larger adenomas.

Question 26

What are the microscopic findings of pituitary adenomas?

Answer 26

- Adenomas are composed of uniform, polygonal cells arrayed in sheets, cords, or papillae. - Sparse supporting reticulin > soft consistency. - The nuclei of the neoplastic cells may be uniform or pleomorphic. - The cytoplasm of the constituent cells may be acidophilic, basophilic, or chromophobic. - The cytoplasm is uniform throughout of the neoplasm.

Question 27

What distinguishes pituitary adenomas from non-neoplastic anterior pituitary parenchyma?

Answer 27

The cellular monomorphism and the absence of a significant reticulin network.

Question 28

What is the difference in reticulin between normal pituitary and pituitary adenoma?

Answer 28

- Normal pituitary > intact reticulin network surrounding the acini. - Pituitary adenoma > breakdown of the reticulin network around the acini.

Question 29

What is the most common pituitary adenoma?

Answer 29

Prolactinomas are the commonest hyperfunctioning pituitary adenoma.

Question 30

Prolactinomas range from _______ to ________.

Answer 30

Microadenoma to macroadenoma.

Question 31

List the signs and symptoms associated with prolactinomas?

Answer 31

Amenorrhea, galactorrhea, infertility, hyperprolactinemia.

Question 32

List other causes of hyperprolactinemia?

Answer 32

1- Pregnancy, lactotroph hyperplasia. 2- Dopamine inhibitors e.g. (Tx, dopamine agonist).

Question 33

What is the second most common type of pituitary adenoma?

Answer 33

Growth hormone-producing adenoma, are the second most common type of functional pituitary adenoma.

Question 34

GH stimulates the secretion of what?

Answer 34

Stimulates the hepatic secretion of insulin-like growth factor I (somatomedin C).

Question 35

What are the clinical manifestations of growth hormone producing adenomas?

Answer 35

1- Before the epiphyses close > gigantism. 2- After the epiphyses close > acromegaly. 3- abnormal glucose tolerance > diabetes mellitus.

Question 36

Which hormone is demonstrable in a number of growth hormone producing adenomas?

Answer 36

Prolactin.

Question 37

Which type of adenomas are microadenomas at the time of diagnosis?

Answer 37

Corticotroph cell adenomas.

Question 38

List the 3 clinical manifestations associated with corticotroph cell adenomas?

Answer 38

1- Cushing syndrome (hypercortisolism). 2- Cushing disease (excessive production of ACTH by the pituitary). 3- Nelson syndrome (corticotroph adenomas may develop after surgical removal of the adrenal glands).

Question 39

List 4 other types of anterior pituitary neoplasms?

Answer 39

1- Gonadotroph (LH & FSH) producing adenomas. 2- Thyrotroph (TSH) producing adenoma > hyperthyroidism. 3- Nonfunctioning pituitary adenomas (silent gonadotroph adenoma) and true hormone-negative (null cell) adenomas). 4- Pituitary carcinomas are exceedingly rare.

Question 40

List 7 causes of hypopituitarism?

Answer 40

Congenital or aquired. 1- Hypothalamic origin (DI). 2- Nonfunctioning pituitary adenomas. 3- Ischemic necrosis (sheehan syndrome) < due to blood loss after delivery). 4- Radiation. 5- Inflammation (sarcoidosis or tuberculosis). 6- Trauma. 7- metastatic neoplasms.

Question 41

List 6 manifestations of hypopituitarism?

Answer 41

1- Pituitary dwarfism (low GH). 2- Amenorrhea and infertility in women (low FSH & LH). 3- Hypothyroidism (low TSH). 4- Hypoadrenalism (low ACTH). 5- Failure of postpartum lactation (low prolactine). 6- Pallor (low MSH).

Question 42

List 2 disorders of the neurohypophysis (posterior pituitary)?

Answer 42

1- ADH deficiency > DI. 2- Secretion of inappropriately high levels of ADH (SIADH).

Question 43

How does ADH deficiency cause diabetes insipidus?

Answer 43

Low ADH > low reabsorption of water in collecting tubules of the kidney > polyuria, low specific gravity, high osmolality, thirst and polydipsia > diabetes insipidus.

Question 44

List 4 causes of diabetes insipidus?

Answer 44

1- Head trauma. 2- Neoplasms. 3- Inflammatory disorders. 4- Surgical procedures or idiopathic.

Question 45

What is syndrome of inappropriate ADH (SIADH)?

Answer 45

High ADH > high reabsorption water > hyponatremia, cerebral edema, neurologic dysfunction & high total body water > SIADH.

Question 46

List 2 causes of SIADH?

Answer 46

1- Secretion of ectopic ADH by malignant neoplasms (small-cell carcinoma of the lung) (paraneoplastic syndrome). 2- Local injury to the hypothalamus and/or neurohypophysis.