01-14 PATH of the Pituitary

Question 1

Do adenomas and carcinomas usually cause hyper- or hypo- function?

Answer 1

usually HYPER

—sometimes hypo via mass effect

Question 2

How common are tumors in ant vs. post pit?

Answer 2

more common in ant pit; very rare in post

Question 3

Pituitary adenomas 101
—size?
—hormone functionality?
—invasive?

Answer 3

SIZE: small or large
FXN: can produce hormones (either just one or many even though clonal!) or not
INV: can be circumscribed OR INFILTRATIVE, which is unique compared to adenomas anywhere else in the body which are by definition NOT infiltrative
—infiltrative does NOT mean it is malignant here

Question 4

List which ant. pit cells become adenomas by degree of frequency

Answer 4

42% Lactotrophs
34% null-cell/chromophobes
10% pleurihormonal
5% Corticotrophs
<5% somato, mammo-somato, gonado, of thyro

Question 5

Somatotroph adenoma
—S/Sx
—Histo

Answer 5

S/SX
—orangomegaly
—skeletal thickening/overgrowth (if skeletally immature → gigantism)
—HTN/cardiac failure
—weakness

HISTO
—monomorphic, nicely vascularized not 100% tumors cells
—stain for GH, PIT-1

Question 6

Corticotroph adenoma
—S/Sx
—Histo

Answer 6

S/Sx
—May be really small (i.e. not seen on imaging) and still potent
—Cushing’s DISEASE: central obesity, moon fascies, purple striae, IGT, depression/emotional lability, etc.
—Remember: excess CRH → excess ACTH → hyperpigmentation

HISTO
—similar to somatotroph

Question 7

Craniopharyngioma

Answer 7

—due to still active cell rest from Rathke's pouch
—often cystic
—hard to resect
—not malignant
—crankcase oil

HISTO
—looks like embryological tissue
—reticular (web-like) formations
—pallisading around vasculature
—Wet keratin

Question 8

Sheehan’s Syndrome
—A.K.A.?
—Presentation
—Pathophys

Answer 8

A.K.A.
—post-partum pituitary necrosis

PRESENTATION
—present ~1wk to 1mo post-partum w/ panhypopituitarism

PATHOPHYS
—massive uterine hemorrhage (hypotens +/- DIC)
—pituitary hemorrhage and infarction = Necrosis & atrophy (so hypofunction vs. hyperfunction w/ tumors/hyperplasia) **?autoimmunity here
—loss of FSH, LSH, ACTH(MSH), TSH, Prl, GH, ADH and Oxytocin (panhypopituitarism)
—end organ atrophy
—hypothyroid, Addison’s, amenorrhea, etc

Question 9

Why is pit vulnerable in preg?

Answer 9

Three Reasons:

1. pit hyperplastic in preg (need more lactrotrophs)
2. something about pit hypothalamic portal system ∆s its blood flow in preg? ask Stefan
3. DIC

Question 10

Empty Sella

Answer 10

pituitary atrophy
—can be 2°radiation, Sheehan’s if ♀ survived
—not same as radiology term “empty sella” which just means you can’t see it”

Question 11

If you have panhypopituitarism, what ∆s will occur in the adrenal gland?

Answer 11

cortex atrophies to just a few mm

—zona glomerulosa likely does NOT atrophy? b/c aldosterone is not under hypothalamic/pituitary control