Pituitary

Question 1

Anterior pituitary

• Aka?
• Derived from?
• Secretes which two types of hormone?
• Give examples of each

Answer 1

Adenohypophysis
Derived from Rathke’s pouch
Secretes trophic and non-trophic hormones
- Trophic: TSH, ACTH, FSH, LH
- Non-trophic: GH and Prolactin

Question 2

Posterior pituitary

• Aka?
• Extension of what?
• What does it secrete?

Answer 2

Neurohypophysis
Extension of neural tissue consists of modified glial cells and axonal processes
Secretes ADH (vasopressin) and oxytocin

Question 3

Anterior pituitary

• Give two causes of hyperfunction
• Give five causes of hypofunction

Answer 3

Hyperfunction
- Adenoma – far more common than carcinoma
- Carcinoma
Hypofunction
- Surgery/radiation - Sudden Haemorrhage into gland
- Ischaemic necrosis - Sheehan Syndrome
- Tumours extending into sella turcica 
- Inflammatory conditions (Sarcoidosis)

Question 4

Give two disorders of the posterior pituitary

Answer 4

Diabetes Insipidus
- Lack of ADH secretion
- Can lead to life threatening dehydration
Syndrome of Inappropriate ADH secretion (SIADH)
- Ectopic secretion of ADH by tumours
- Primary disorder in the pituitary

Question 5

Pituitary adenoma

• Derived from which cells?
• Common or rare?
• Can be associated with which genetic abnormality?
• How can they be classified?
• What can large adenomas cause?

Answer 5

Derived from cells of anterior pituitary.
Relatively common (10% intra-cranial tumours).
Sporadic or associated with MEN1 (Wermer syndrome).
Classify by cell type / hormone produced
- Prolactin (20-30%)
- ACTH (10-15%)
- FSH/LH (10-15%)
- GH (5%)
- Can produce more than one
- Can be hypo / non-functional (25-30%) – later presentation
- Hormone production may be at subclinical levels
Large adenomas can cause:
- Visual field defects
- Pressure atrophy of surrounding normal pituitary tissue – if you don’t treat quickly, then this can occur and leave lasting damage
- Infarction can lead to panhypopituitarism

Question 6

Functional pituitary adenomas

• What is the most common and what symptoms does it cause?
• What is the second most common and what symptoms does it cause?

Answer 6

Prolactinoma - infertility, lack of libido, amenorrhea

GH secreting - gigantism or acromegaly

Question 7

Pituitary hypofunction

• What is the most common cause?
• Give some other causes

Answer 7

Panhypopituitarism
Other causes
- Primary or metastatic tumours - Rathke cleft cysts
- Traumatic brain injury
- Subarachnoid haemorrhage
- Surgery or radiation
- Granulomatous inflammation – sarcoidosis, tuberculous meneingitis
- Infarction / Haemorrhage

Question 8

Craniopharyngioma

• Derived from?
• What % of all intracranial tumours?
• Features of the tumour itself?
• Who gets it?
• Symptoms?
• Prognosis?

Answer 8

Derived from remnants of Rathke’s pouch.
1 – 5% of intracranial tumours.
Slow growing, often cystic, may calcify – can be a clue to the nature of the disease.
Bimodal incidence
- 5 -15 years age
- 6th – 7th decades
Headaches and visual disturbances - children may have growth retardation.
Excellent prognosis (especially if <5cm).