Flashcards in Pathology of Pituitary and Adrenal Glands Deck (63)
What is a pituitary adenoma?
- benign tumor of ANTERIOR pituitary cells
- may be FUNCTIONAL (produces hormones) or NONfunctional (does not produce hormones)
**** How do NONfunctional pituitary adenomas present?
with mass effect:
- BITEMPORAL HEMIANOPSIA (due to proximity of optic chiasm to sella turcica).
How do FUNCTIONAL pituitary adenomas present?
- features based on hormone produced.
**** What is a Prolactinoma?
most common type of functional pituitary adenoma causing:
- galactorrhea and amenorrhea due to prolactin's inhibition of GnRH, decreasing FSH and LH (females)
- decreased libido and headache (males)
- may undergo DYSTROPHIC CALCIFICATION (calcium deposition with normal serum calcium) with psammoma bodies
- AMYLOID deposition (apple green birefringence)
- PERINUCLEAR CRESCENTS of prolactin immunopositivity
How do you treat a prolactinoma?
- dopamine agonists; bromocriptine (inhibits prolactin secretion) or surgery
*** What is a Growth Hormone adenoma?
functional pituitary adenoma causing:
- GIGANTISM in children
- ACROMEGALY in adults
- T2DM (GH causes decreased glucose uptake in cells)
*** How do you diagnose Growth Hormone adenoma?
- elevated GH and IGF-1
- oral glucose will NOT suppress GH release.
How do you treat GH adenoma?
- OCTREOTIDE (somatostatin analog that blocks the response of the anterior pituitary to GHRH).
- GH receptor antagonists
What are some other FUNCTIONAL pituitary adenomas?
- ACTH cell adenomas= secrete ACTH leading to hypersecretion of cortisol (Cushing disease). Hyperpigmentation due to ACTH precursor products on melanocytes.
- Thyrotroph= TSH
*LH and FSH-producing adenomas are rare.
What is HYPOpituitarism?
- insufficient production of hormones by anterior pituitary.
**** What can cause HYPOpituitarism?
- pituitary adenoma (adults)
- CRANIOPHARYNGIOMAS (children)= slow growing cystic tumors (cholesterol crystals, keratin, peripheral palisading) arising from suprasellar regions, causing headaches and visual problems.
- SHEEHAN SYNDROME= infarcted pituitary due to increase in size during pregnancy, but lack of blood flow increase; women present with poor lactation and loss of pubic hair.
- EMPTY SELLA SYNDROME= defect in the diaphragm sella allowing the arachnoid mater CSF to herniate into the sella, expanding the sella and compresses the pituitary, leading to PANHYPOPITUITARISM (hypothyroidism, adrenal insufficiency, amenorrhea).
*** What are the POSTERIOR pituitary pathologies?
- central diabetes insipidus
*** What is Central Diabetes Insipidus?
- increased urination (polyuria) and increased thirst (polydipsia) due to ADH deficiency (due to hypothalamic or posterior pituitary pathology).
- hypernatremia and high serum osmolality.
- low urine osmolality and specific gravity.
How do you diagnose Central Diabetes Insipidus?
- water deprivation fails to increase urine osmolality.
How do you treat Central Diabetes Insipidus?
- Desmopressin (ADH analog).
*** What is nephrogenic diabetes insipidus?
- impaired renal response to ADH due to inherited mutations or drugs (lithium).
*similar to central DI, but there is no response to desmopressin.
*** What is SIADH (syndrome of inappropriate ADH secretion)?
- excessive ADH secretion leading to hyponatremia, low serum osmolality, mental status change, and seizures (from cerebral edema).
*** What can cause SIADH?
- ectopic production (small cell carcinoma of the lung).
- CNS trauma
- pulmonary infection or pathology (COPD)
- drugs (cyclophosphamide)
How do you treat SIADH?
- free water restriction
- demeclocycline (blocks effect of ADH).
What is pituitary apoplexy?
- bleeding into an adenoma
What genetic components lead to pituitary adenomas?
- G alpha proteins generating cAMP, which is a mitogenic stimulus due to GNAS mutation interfering with intrinsic GTPase activity, which hydrolyzes GTP (required for cAMP generation) to GDP.
What genetic products are associated with familial pituitary adenomas?
- CDKN1B= MEN like syndromes
- PRKAR1A= Carney's syndrome
- AIP= GH adenomas
What is the morphology of adenomas?
- cellular monomorphism and absence of a reticulin network.
What is hypopituitarism?
- decreased secretion of pituitary hormones.
What percentage of parenchyma must be lost for hypofunction of the anterior pituitary to occur?
What is a Rathke cleft cyst??
- cysts lined by ciliated cuboidal epithelium, which can expand and compress the normal gland.
Are most metastatic pituitary tumors symptomatic?
NO, they are mostly asymptomatic.
What are the 3 layers of the ADRENAL CORTEX?
1. Glomerulosa= aldosterone (mineralocorticoids)
2. Fasiculata= cortisol (glucocorticoids)
3. Reticularis= sex steroids
*remember GFR and all hormones are synthesized from cholesterol here ("gets sweeter as you get deeper").
**** What is CUSHING Syndrome and what are the clinical features? (PICMONIC)
Excess cortisol causing:
- muscle weakness with thin extremities (due to breaking down muscle for gluconeogenesis).
- moon facies, buffalo hump, and truncal obesity (due to excess glucose in the blood causing excess production of insulin leading to excess storage of fat).
- abdominal striae (cortisol impairs the synthesis of collagen, leading to easily ruptured blood vessels).
- HTN (cortisol upregulates alpha 1 receptors on arterioles increasing the effect of norepinephrine)
- Immune suppression