Background

Question 1

What is the % of pituitary tumors in relation to all primary brain tumors?

Answer 1

∼10%–15% of all diagnosed primary brain tumors are of pituitary origin with up to 25% seen on autopsy series.

Question 2

What % of pituitary tumors are functional vs. nonfunctional?

Answer 2

75% of pituitary tumors are functional, while 25% are nonfunctional.

Question 3

What are the sex and age predilection for pituitary tumors with symptomatic presentations?

Answer 3

Symptomatic pituitary tumors occur mostly in females. 70% occur from 30–50 yrs.

Question 4

What is a heritable syndrome that predispose to pituitary tumors, and what is the inheritance pattern?

Answer 4

MEN-1 (3 “Ps”: pituitary, parathyroid, pancreas), 11q13 mutant/menin. Autosomal dominant inheritance.

Question 5

What is Nelson syndrome?

Answer 5

Nelson syndrome is ACTH-secreting adenoma that develops after adrenalectomy (pts can develop hyperpigmentation of the skin d/t a melanocyte-stimulating hormone). These may be less responsive to RT.

Question 6

What are the embryonic derivatives of the ant pituitary vs. post pituitary?

Answer 6

Anterior: Rathke pouch (oral ectoderm)

Posterior: extension of the 3rd ventricle (neuroectoderm)

Question 7

What is the name for the bony structure that houses the pituitary?

Answer 7

The sella turcica houses the pituitary.

Question 8

What are the boundaries of the sella?

Answer 8

Tuberculum sellae anteriorly, dorsum sellae posteriorly, sphenoid sinus inferiorly, dural folds superiorly, and post clinoid processes laterally.

Question 9

What CN deficit is most commonly caused by pituitary adenoma?

Answer 9

CN II. Pituitary adenomas are the most common cause of optic chiasm compression. Less commonly, CN III, CN IV, and CN VI deficits can cause ocular motility Sx.

Question 10

What hormones are secreted by lobes of the pituitary?

Answer 10

Anterior: prolactin (PL), GH, ACTH, TSH, LH, FSH

Intermediate: melanocyte-stimulating hormone (MSH)

Posterior: ADH, oxytocin

Question 11

What is the histopathologic description of the cells of nonfunctional tumors?

Answer 11

Histopathologically, the cells of nonfunctional tumors are chromophobic.

Question 12

What hormones are secreted by basophilic cells? Acidophilic cells?

Answer 12

Basophilic: ACTH, TSH, LH, FSH

Acidophilic: GH, PL

Question 13

What is the most common functional pituitary tumor? 2nd most common? 3rd most common?

Answer 13

Prolactinoma (30%) > GH (25%) > ACTH (∼15%)

Question 14

Which pituitary tumors are more common in males and the elderly? Which are more common in females?

Answer 14

Males and the elderly: nonfunctioning or GH

Females: PL and ACTH secreting

Question 15

Which are the more common pituitary tumors: micro- or macroadenomas?

Answer 15

Macroadenomas (≥1 cm) are the more common pituitary tumors.

Question 16

Which are the most common pituitary tumors in females?

Answer 16

Microadenomas (<1 cm) are the most common pituitary tumors in females, particularly those that are PL secreting.

Question 17

What is the most common cause of pituitary dysfunction in adults? Children?

Answer 17

Adults: pituitary adenoma

Children: craniopharyngioma

Question 18

What histologic features are prominent in prolactinomas?

Answer 18

Calcifications and amyloid deposits are prominent in prolactinomas.

Question 19

What immunohistochemical stains are positive in pituitary adenomas?

Answer 19

Synaptophysin, chromogranin, and hormone-specific stains