Pituitary tumours

Question 1

How are tumours tested for classification

Answer 1

MRI

Question 2

How are pituitary adenomas classified?

Answer 2

Microadenoma <1cm. Macroadenoma >1cm. Sellar or supracellar. Invading cavernous sinus or not. compressing optic chiasm?

Question 3

What is the name of a functioning somatotroph adenoma?

Answer 3

Increased growth hormone secretion resulting in acromegaly

Question 4

What is the name of a functioning lactotroph adenoma?

Answer 4

Increased prolactin secretion and prolactinoma

Question 5

What is the name of a functioning thyrotroph adenoma?

Answer 5

Increased TSH secretion resulting in TSHoma

Question 6

What is the name of a functioning gonadotropin adenoma?

Answer 6

Increased LH and FSH resulting in gonadotrophinoma

Question 7

What is the name of a functioning Corticotroph adenoma?

Answer 7

increased ACTH secretion resulting in Cushing’s disease, corticotroph adenoma

Question 8

How does hyperprolactinaemia result in oligo-amenorrhoea, low libido, infertility and osteoporosis?

Answer 8

Prolactin binds to prolactin receptors on kisspeptin neurons in the hypothalamus, inhibiting kisspeptin release. This results in a decrease in downstream GnRH/LH/FSH, which in turn results in a decrease in oestrogen/ testosterone

Question 9

How does a prolactinoma present and what serum prolactin levels would be found in the blood?

Answer 9

> 5000 mU/L , proportional to the tumour size. Presents with menstrual disturbance/erectile dysfunction, reduced libido, galactorrhoea, subfertility

Question 10

When should a pituitary MRI be ordered for someone with a suspected prolactinoma?

Answer 10

Once confirmed a true pathological elevation of serum prolactin

Question 11

Other than a prolactinoma, what are other causes of elevated prolactin?

Answer 11

Physiological: pregnancy, stress, exercise, seizure, primary hypothyroidism, PCOS, chronic renal failure,SSSRIs, anti-emetics, opiates, high dose oestrogen

Question 12

How can a prolactinoma be treated?

Answer 12

Dopamine receptor agonists.

Question 13

How does acromegaly present?

Answer 13

Often insidious presentation, mean time to diagnosis = 10 years, sweatiness, headache, coarsening of facial features, increase in hand and feet size, macroglossia, hypertension, obstructive sleep-apnoea, impaired glucose tolerance

Question 14

How is acromegaly diagnosed?

Answer 14

Clinical symptoms and measurements, failed suppression (paradoxical rise) of GH following oral glucose load.

Question 15

True or false, you can measure random serum GH to diagnose acromegaly?

Answer 15

GH is pulsatile therefore random measurements are unhelpful

Question 16

How is acromegaly treated?

Answer 16

First line treatment is surgical, a trans-sphenoidal pituitary surgery, which aims to normalise serum GH and IGF-1. Can use medical treatment such as somatostatin analogues and dopamine agonists

Question 17

What are the two types of causes of Cushing’s syndrome?

Answer 17

Can be ACTH dependent or ACTH independent

Question 18

What are some ACTH dependent causes of Cushing’s disease?

Answer 18

Corticotroph adenoma, ectopic ACTH (lung cancer)

Question 19

What are some ACTH independent causes of Cushing’s disease?

Answer 19

Taking steroids by mouth, adrenal adenoma or carcinoma

Question 20

What are the symptoms of Cushing’s disease?

Answer 20

Moon face, reddened cheeks, central obesity, buffalo hump, proximal myopathy resulting in the inability to stand from a squat, easy bruising, purple striae,

Question 21

What is the difference between Cushing’s syndrome and cushings disease?

Answer 21

Syndrome = excess cortisol, disease = corticoadenoma secreting ACTH

Question 22

How do we investigate Cushing’s disease?

Answer 22

Elevated 24h urine free cortisol, elevated late night cortisol, failure to suppress cortisol after oral dexamethasone. Once confirmed hypercorticolism, measure ACTH, if ACTH high pituitary MRI ACTH dependent

Question 23

How do non-functioning pituitary adenomas present?

Answer 23

Often with visual disturbance (bitemporal hemianopia), can present with hypopituitarism, serum prolactin can be raised

Question 24

Why can serum prolactin be raised in non-functioning pituitary adenomas?

Answer 24

Dopamine cant travel down pituitary stalk from hypothalamus

Question 25

How are non-functioning pituitary adenomas treated?

Answer 25

Trans-sphenoid all surgery needed for large tumours, particularly if visual disturbance

Question 26

How do we know if a pituitary tumour is benign or malignant?

Answer 26

Pituitary carcinoma very rare, mitotic index measured using Ki67 index, benign is <3%. Pituitary adenomas can have benign histology but display malignant behaviours

Question 27

What percentage of pituitary tumours are carcinomas?

Answer 27

<0.5%

Question 28

How do dopamine receptor agonists work to fight prolactinoma?

Answer 28

Act on D2 receptors to decrease prolactin secretion