Endocrine CPC

Question 1

What is the MEN1 mutation and what conditions are associated with it?

Answer 1

Most common endocrine genetic issue - loss of function of the menin (tumour suppressor) gene
Get parathyroid adenomas (most common), pituitary adenomas and pancreatic islet cell tumours

Question 2

What is the Gs alpha mutation and what is it associated with?

Answer 2

GPCR component overactivity, causing hypersecretion

Associated with 40% of somatotroph adenomas

Question 3

What are the basic principles of endocrine dynamic testing?

Answer 3

To evaluate deficiency: test when supposed to be high or with a stimulation test (eg. Synacthen test or morning cortisol/ACTH)
Excess: test when supposed to be low or suppression test (eg. midnight salivary cortisol or dexamethasone suppression test)

Question 4

What are the % causes of ACTH-independent Cushing’s?

Answer 4

50% benign adenoma
40% adrenal carcinoma
5% micronodular hyperplasia
3% macronodular hyperplasia

Question 5

What are the % causes of ACTH-dependent Cushing’s?

Answer 5

84% Cushing’s disease (ie. pituitary tumour)
15% ectopic ACTH (small cell lung tumour #1)
1% ectopic CRH