Pituitary tumours

Question 1

what is the epidemiology?

Answer 1

10% intracranial tumours

Question 2

state the aetiology

Answer 2

• micro-adenoma (<1cm)

* macro-adenoma (>1cm)

Question 3

What are the 3 histological types of tumours?

Answer 3

• Chromophobe (70%): non-secretory, prolactin secreting (50%) or GH (acromegaly) or ACTH (Cushing’s disease) (RARE), local pressure affect is 30,
• Acidophil (15%): secrete GH or prolactin, local pressure effect in 10%
• Basophil (15%): secrete ACTH, local pressure effect is rare

Question 4

what are the signs and symptoms that occur from the local pressure?

Answer 4

• headache
• bitemporal hemianopia (compression of optic chiasm)
• CN III, IV, V and VI palsies (cavernous sinus pressure), - diabetes insipidus (hypothalamic disease), - sleep and appetite being affected
• CSF rhinorrhoea (erosion of floor through sella)

Question 5

what are some signs and symptoms that are caused by hormones?

Answer 5

• Prolactin: galactorrhoea, reduced libido, amenorrhoea, erectile dysfunction (prolactin inhibitor GnRH secretion causing reduced FSH and LH)
• GH: acromegaly
• ACTH: Cushing’s disease

Question 6

what investigations are performed?

Answer 6

• Hormones: prolactin, GH, ACTH, cortisol, TFT (secondary hypothyroidism occurs as pituitary tumour invades gland, stopping it from making other hormones), LH and FSH, short synacthen test
• Suppression tests:

o Glucose tolerance test: assesses for acromegaly

o 48h high dose dexamethasone suppression test: suppression in Cushing’s disease

o Water deprivation test: assesses for diabetes insipidus

• MRI pituitary fossa: defines intra and supra sellar extension

Question 7

what is the management?

Answer 7

• Medical: hormone replacement (always give steroids BEFORE levothyroxine as can precipitate adrenal crisis)
• Surgery: transphenoidal excision with pre-op HYDROCORTISONE and post-op pituitary testing and dynamic adrenal testing at 6w post-op dopamine agonist 1st line for prolactinoma
• Radiotherapy: residual or recurrent adenomas

Question 8

discuss the post-op

Answer 8

• recurrence may occur late after surgery, so life-long follow up is required.
• fertility should be discussed - this may be reduced post-op due to decrease in gonadotrophins

Question 9

discuss pituitary apoplexy

Answer 9

haemorrhage into pituitary tumour causing mass effects (headache, Meningism, reduced GCS, bi-temporal hemianopia) and adrenal crisis causing cardiovascular collapse.

Treatment is URGENT IV HYDROCORTISONE

Question 10

discuss craniopharyngioma

Answer 10

• Not strictly a pituitary tumour.
• originates from Rathke’s pouch - between pituitary and 3rd ventricle floor
• RARE - but comments childhood intercranial tumour
• Children - over 50% have growth failure
• adults - amenorrhea, dec libido, hypothalamic symptoms (eg diabetes insidious, hyperphagia, sleep disturbance) or tumour mass effect

Tests - CT/MRI (classification in 50% may also be seen on skull X-ray)

Treatment - Surgery and/or post-op radiation; also test pituitary function post-op