Endocrine System & Pituitary Pathology

Question 1

Hypothalamic-Pituitary Axis Hormones

Stimulating (3) and Inhibitory (2)

Answer 1

Stimulating:
Thyroid Releasing Hormone (releases TSH)
Corticotropin Releasing Hormone (releases ACTH)
Gonadotropin Releasing Hormone (releases GH/LH/FSH)

Inhibitory:
PIF/Dopamine (blocks Prolactin)
Gonadotropin Inhibiting Hormone (blocks GH)

Question 2

Hypothalamic-Pituitary Axis Anatomical Features (3)

Answer 2

Hypophyseal Portal Veins carry hormones from hypothalamus to anterior pituitary gland

Hypothalamic Artery and Superior Hypophyseal Artery carry blood back to hypothalamus which regulates hormone release

Question 3

Pituitary Adenohypophysis and Neurohypophysis
Cell Types (3/2) with Hormones Released

Answer 3

Adenohypophysis:
Acidophils: Somatotrophs (GH), Mammosomatotrophs (PRL)
Basophils: Thyrotrophs (TSH), Gonadotrophs (LH/FSH), Corticotrophs (ACTH)
Chromophobes: can release any hormones

Neurohypophysis:
Axonal neurons (release ADH and Oxytocin)
Supportive Pituicytes

Question 4

Hyperpituitarism Etiologies (5)

Answer 4

Pituitary Adenoma (most common)
Anterior Pituitary Hyperplasia
Anterior Pituitary Carcinomas
Nonpituitary tumor hormone secretion
Hypothalamic disorders

Question 5

Pituitary Adenomas

Peak Age, Mass Effect Symptoms (9) and Size Categorizations (3)

Answer 5

Adults aged 35-60

Increased Intracranial Pressure causing:
Headaches, N/V
HTN and Bradycardia
Shallow Breathing
Papilledema
Bitemporal Hemianopsia
Pituitary Apoplexy
Hyperprolactinemia

Microadenoma if < 1 cm
Macroadenoma if >1 and < 4 cm
Giant Adenoma if > 4 cm

Question 6

Pituitary Adenoma
Genetic Mutations with Effects
Gain of Function (3) and Loss of Function (4)

Answer 6

Gain:
GNAS - Increased cAMP via Gs-alpha losing GTPase
PRKAR1A - Increased cAMP via PKA
Cyclin D1 - Promotes G1-S in cell cycle

Loss:
MEN1 - Decreased menin which increases JunD
AIP - loss of aryl hydrocarbon receptor
CDKN1B - Decreased p27 cell cycle regulation
RB - loss of RB cell cycle regulation

Question 7

Lactotroph Adenoma (Prolactinoma)
Male (3) and Female (5) Presentation

Answer 7

*Most common pituitary adenoma

Women: 
Menstrual Irregularities
Galactorrhea
Diminished Libido
Infertility
Mass effect

Men:
Decreased libido
Decreased sperm count
Mass effect (headaches)

Question 8

Lactotroph Adenoma
Histologic Features (4) and Treatment (2)

Answer 8

Sparsely Granulated (most common classification)
Densely Granulated
Stromal hyalinization with psammoma bodies
Dense calcification causing pituitary stone

Dopamine agonists
Surgical resection

*Most common pituitary adenoma

Question 9

Somatotroph Adenoma (GH)
Associated Conditions (2) with Clinical Descriptions (1/7)
Diagnosis (2) and Treatment (3)

Answer 9

Gigantism: seen in child has somatotroph adenoma

Acromegaly:
Seen in adults with somatotroph adenoma
Enlarged face/hands/nose
Protruding jaw
Thick lips
Joint pain/immobility
Enlarged viscera
Shortened life

Elevated serum IGF test
Oral glucose tolerance test for GH

Somatostatin analogs
GH receptor antagonists
Surgical resection

Question 10

Corticotroph Adenoma (ACTH)
Associated Syndromes (3), Clinical Features (6)
Diagnosis (2) and Treatment (3)

Answer 10

Cushing disease 
Cushing Syndrome (mostly from exogenous ACTH)
Nelson Syndrome (Pituitary adenoma post-adrenal resection for Cushing syndrome treatment)

Hypercortisolism causing:
Moon facies
Centripetal obesity
Striae
Hirsutism
Thin skin

Responsive to high dose dexamethasone inhibition
Elevated response to CRH

Somatostatin analog
Bromocriptine
Surgical resection

Question 11

Gonadotroph Adenoma (LH/FSH)
Clinical Features (4)

Answer 11

Often asymptomatic
Mass effect symptoms
Decreased libido in men
Amenorrhea in women

Question 12

Thyrotroph Adenomas (TSH)
Clinical Description (2)

Answer 12

Uncommon pituitary adenoma

Causes hyperthyroidism

Question 13

Non-Functional Adenomas
Clinical Features (2)

Answer 13

Mass Effect symptoms

Hypopituitarism (if it compromises Anterior Pituitary)

Question 14

Pituitary Carcinoma
Clinical Features (4) and Prognosis

Answer 14

Craniospinal or systemic metastases
Elevated PRL or ACTH

Poor prognosis, can spread into brain

Question 15

Hypopituitarism Etiologies with Explanations

Lesions (3), Empty Sella (2), Sheehan (2)

Answer 15

Mass lesions: Rathke cleft cyst, Glioma, Craniopharyngioma

Empty Sella Syndrome
Primary: CSF compresses Anterior Pituitary
Secondary: Pituitary adenoma grows into sella

Sheehan Syndrome
Postpartum ischemic necrosis of Pituitary
Due to compression of venous supply

Question 16

Hypopituitarism Clinical Features by Hormone

GH (3), LH/FSH (6), TSH (3), ACTH (3), PRL (1)

Answer 16

GH: increased body fat, decreased muscle and strength

LH/FSH: poor libido, infertility, amenorrhea, dyspareunia, reduced body hair, breast atrophy

TSH: Decreased energy, constipation, weight gain

ACTH: weakness, tiredness, hypoglycemia

PRL: Lactation failure

Question 17

Diabetes Insipidus

Etiologies (4) Pathophysiology (2), Clinical Features (3)

Answer 17

Head trauma
Mass lesions
Inflammation of hypothalamus or posterior pituitary
Surgical Complications

Central: insufficient ADH release from PP
Nephrogenic: Renal Tubule unresponsive to ADH

Dilute polyuria
Elevated serum Sodium and osmolality
Polydipsia

Question 18

SIADH

Etiologies (3) Pathophysiology (2) and Clinical Features (6)

Answer 18

Small cell lung carcinoma
Traumatic brain injury
SSRI’s

Excessive ADH release causes excessive free water retention causing hyponatremia

Decreased serum osmolality
Concentrated urine
Mental status change
Muscle weakness
Seizures
Inapprpriate polydypsia

Question 19

Adamantinomatous Craniopharyngioma

Demographic, Presentation and Histology (4)

Answer 19

Kids aged 5-15

Growth retardation from hypopituitarism

Palisading squamous epithelium
Compact, lamellar keratin (wet keratin)
Dystrophic calcification
Cysts with cholesterol rich “machine oil” fluid

Question 20

Papillary Craniopharyngioma

Demographic, Presentation (2) and Histology (2)

Answer 20

Adults aged 65+

Increased intracranial pressure, hypopituitarism

Solid sheets of cells
Papillae lined by well differentiated squamous epithelium