Lecture: Pituitary pathology Flashcards
Where is the pituitary gland located?
sella turnica in the sphenoid bone
What part of the pituitary has a direct connection with the hypothalamus?
The posterior pituitary
Describe the arterial supply to the anterior pituitary.
It does not have one, only portal venous drainage.
percentage of pituitary that is the anterior pituitary?
makes up about 80% of the gland
What is the embryological origin of the anterior pituitary?
Derived embryologically from Rathke’s pouch.
Eventually cut-off from its origin by the growth of the sphenoid bone.
Describe blood supply to anterior pituitary.
A portal vascular system – carries hypothalamic releasing hormones from the hypothalamus to
the pituitary gland.
What part of the pituitary produces oxytocin and ADH?
Posterior pituitary
Describe the structure of the posterior pituitary
Composed of modified glial cells known as pituicytes. Additionally axonal processes extending from nerve cell bodies in the hypothalamus, through the pituitary stalk to the posterior lobe these neurons produce ADH and oxytocin – stored in axon terminals in the posterior pituitary and are released into the circulation in response to appropriate stimuli
Causes of hypopituitarism?
ischaemia; surgery; radiation; inflammation; compression by nonfunctional adenomas.
Name six types of pituitary tumours
- Pituitary adenoma
- Pituitary carcinoma
- Gangliocytoma
- Mesenchymal tumours
- Granular cell tumours
- Secondary tumours
Most common cause of hyperpituitarism?
Pituitary adenoma
What can – pituitary hyperplasia – carcinomas of the anterior pituitary – secretion of hormones by extra-pituitary tumours – certain hypothalamic disorders all cause?
Hyperpituitarism
Most common age demographic for pituitary adenomas?
Adults 30 - 50 years
What percentage of pituitary adenomas are associated with MEN1 mutations
• 3% of adenomas are associated with MEN1 • germline mutation of MEN1 on chr 11q13 • autosomal dominant inheritance – pancreas • 50% G cell tumours • 30% beta cell tumours • 12% VIP cell tumours – parathyroid • chief cell hyperplasia
When is a pituitary adenoma defined as a macroadenoma rather than a microadenoma?
Greater than 1 cm
Name three locations in which ectopic pituitary adenomas can form.
– diencephalic infundibulum
– the pituitary stalk
– sphenoid bone between the nasopharynx and the pituitary fossa
Gross histological features of pituitary adenoma?
relatively uniform, polygonal cells are arranged in sheets or cords