Endo - Pituitary Tumour Flashcards
What is the outcome of a functioning somatotrophic tumour?
acromegaly
What is a functioning lactotroph tumour called?
prolactinoma
What is a functioning thyrotroph tumour called?
TSHoma
What is a functioning gonadotroph tumour called?
Gonadotrophinoma
What is a corticotroph tumour called?
Cushing’s Disease (corticotroph adenoma)
How do you classify a pituitary tumour by size?
→ microadenoma = < 1 cm
→ macroadenoma = > 1 cm
How do you classify a pituitary tumour radiologically?
→ sellar or suprasellar
→ compressing optic chiasm or not
→ invading cavernous sinus or not
How do you classify a pituitary tumour by function?
→ excess secretion of hormone
→ no excess secretion of hormone = non-functioning adenoma
How do you classify a pituitary tumour by benign or malignancy?
→ carcinoma very rare
→ mitotic index measured using Ki67 index (benign is <3%)
→ pituitary adenoma can have benign histology + malignant behaviour
What the effect of hyperprolactinaemia on the gonadotrophin hormones?
→ Prolactin binds to prolactin receptors on kisspeptin neurons in hypothalamus
→ Inhibits kisspeptin release
→ decreases downstream homrone cascade e.g. less GRH, LH + FSH, testosterone + oestrogen
What is the most common functioning pituitary adenoma?
prolactinoma
What is the size of the prolactinoma usually proportional to?
serum prolactin
How does the prolactinoma present?
→ Menstrual disturbance → Erectile dysfunction → Reduced libido → Galactorrhoea → Subfertility → Oligo-amenorrhoea → Osteoporosis
What are the alternative physiological cause of elevated prolactin?
→ pregnancy / breastfeeding
→ stress (exercise, seizure, venepuncture)
→ nipple/chest wall stimulation
What are the alternative pathological causes of elevated prolactin?
→ primary hypothyroidism
→ polycystic ovarian syndrome
→ chronic renal failure