Pituitary Adenoma Flashcards
Pituitary Disorder
Define Pituitary Adenoma
Benign tumour derived from cells of anterior pituitary - hyperfunction
What are the main causes of pituitary adenomas?
Sporadic
Associated with MEN1
What is the difference between a microadenoma and a macroadenoma?
Microadenoma (<1cm): Less aggressive
Macroadenoma (>1cm):
What are the features of aggressive pituitary adenomas?
Rapid enlargement, high mitotic figures, and p53 mutations
What is a pituitary carcinoma?
A rare (<1%) malignant pituitary tumour, often secreting prolactin or ACTH, which metastasises late
What are the two main types of pituitary adenomas?
- Non-functioning adenomas (25-30%) = no significant hormone secretion, present due to mass effect
- Functioning adenomas
= excess hormone secretion
What visual defect is associated with a large pituitary adenoma?
Bitemporal hemianopia (due to optic chiasm compression)
What is the most common type of functional pituitary adenoma?
Prolactinoma
(lactotroph adenoma, 20-30%)
How does a GH-secreting adenoma present?
Gigantism (children)
Acromegaly (adults)
What syndrome is associated with an ACTH-secreting adenoma?
Cushing’s disease (due to excess cortisol)
What initial blood test should be done for a suspected prolactinoma?
Serum prolactin
= prolactin is often raised due to any cause of dopamine inhibition
What imaging is used to diagnose a pituitary adenoma?
MRI pituitary
= to differentiate micro vs macroadenoma and assess optic chiasm involvement
Why are visual field tests important in pituitary adenoma?
To check for bitemporal hemianopia due to optic chiasm compression
What other hormone tests should be performed in suspected pituitary adenoma?
Full pituitary hormone panel
(GH, ACTH, FSH/LH, TSH)
What is the main treatment for pituitary adenomas?
Transsphenoidal surgery
What additional management is required for patients post-surgery?
Hormone replacement therapy if there is hypopituitarism
Are pituitary adenomas usually benign or malignant?
Benign
What symptoms can arise due to local pressure effects of a pituitary adenoma?
Headaches and visual field defects
What is the best imaging modality for diagnosing pituitary adenomas?
MRI pituitary
What ophthalmic complication can patients with pituitary tumours classically present with?
Bitemporal hemianopia
What is the most common type of pituitary tumour?
Prolactinoma
What is the size cut off to distinguish between micro and macro pituitary adenomas?
10mm
What is the best test to assess pituitary hormone function?
Insulin stress/tolerance test is the gold standard investigation
What is the best initial screening test for growth hormone deficiency?
Serum IGF-1 levels
What is the advised initial hormone replacement therapy in patients with confirmed hypopituitarism?
Cortisol
A 50-year-old man is being reviewed in the endocrine clinic. He was initially referred because of erectile dysfunction and low testosterone but has been found to have multiple hormone deficiencies, including TSH and Cortisol, as well as hypogonatrophic hypogonadism.
As part of his work up, he is referred for a pituitary MRI scan.
What is the most likely diagnosis and why?
Pituitary adenoma
= majority of cases of hypopituitarism are due to pituitary tumours, with adenomas being the commonest type
A 40-year-old man attends his GP because of headaches that have been going on for 3 months. It is also uncovered that he has been experiencing erectile dysfunction and he is low in mood because of this.
Following referral to the Neurologists, he has an MRI scan to investigate his headache. This reveals a pituitary adenoma.
What is the most likely cause for his problems?
Prolactinoma
A 32-year-old woman presents with irregular menstrual periods, milky discharge from her breasts and headaches. She is not currently pregnant but is keen to start a family soon. On examination, she is found to have bitemporal hemianopia.
What is the most appropriate management for the likely diagnosis? and why?
Cabergoline
= The likely diagnosis is a prolactinoma, a benign pituitary tumour that secretes prolactin. Elevated prolactin levels lead to symptoms such as galactorrhoea, irregular periods, and infertility. Cabergoline, a dopamine agonist, is the first-line treatment for reducing prolactin levels and shrinking the tumour, which can help restore normal menstrual cycles and alleviate other symptoms. It is also preferable in patients wishing to conceive.
When wouldn’t MRI pituitary be the best investigation to use?
If the patient is pregnant
= would use Beta-HCG
A 28-year-old woman has been experiencing defects in her visual field. She has also been experiencing headaches, low mood, galactorrhea and secondary amenorrhea, which has been occurring for a year. She has not had any children.
Which visual field defects is she most likely to experience with this condition?
Bitemporal superior quadrantanopia
A 25-year-old woman presents to an endocrinology clinic with a headache, galactorrhoea, and difficulty conceiving. Examination reveals bitemporal hemianopia affecting the upper field more than the lower, whilst investigations show elevated serum prolactin levels.
Considering the anatomy of the pituitary gland, what is the cause of this patient’s visual field defect?
Compression of the optic chiasm from below
