1.6 Disorders of the Hypothalamic Pituitary Axis

Question 1

What are three main classes of pituitary disorders (in terms of downstream effect, not tumour classification)

Answer 1

• Hypersecretion
• Hyposecretion
• Local mass effects due to adenoma

Question 2

True or false: pituitary adenomas are benign, and always stay benign

Answer 2

• False
• Although adenomas themselves are benign, pituitary adenomas can progress into carcinomas as well

Question 3

True or false: due to their symptoms, pituitary adenomas are almost always discovered by patients right away.

Answer 3

• False
• Depends on which hormone is being secreted; often, may go unnoticed until large enough to disrupt sella turcica

Question 4

How are pituitary carcinomas diagnosed?

Answer 4

• NOT based on histology
• Instead, based on evidence of metastases being present

Question 5

How can pregnancy cause ischaemia of the pituitary gland?

Answer 5

• During pregnancy, the anterior pituitary almost doubles in size! (prepares the body for birth, ready for lactation etc.)
• Blood supply (superior hypophyseal artery) remains unchanged
• Supply/demand mismatch leads to ischaemia

Question 6

Craniopharyngiomas are developed from vestigial remnants of…

Answer 6

Rathke’s pouch (where the anterior pituitary was formed)

Question 7

True or false: a pituitary adenoma can produce both growth hormone and prolactin

Answer 7

• True
• In fact, it’s rare to have a growth hormone adenoma that doesn’t also cause prolactin release

Question 8

What are the three broad classes of possible treatment for pituitary adenomas?

Answer 8

1. Medication (e.g. dopamine agonists for prolactinoma)
2. Surgery (to remove adenoma where possible)
3. Radiotherapy (to shrink tumours where possible)

Question 9

Outline 4 methods/modalities of testing hormone levels

Answer 9

• Blood
• Saliva
• Urine
• Imaging (e.g. MRI Pituitary)