Non-Functioning Tumours and Pituitary Hormone Testing Flashcards
where does Craniopharyngioma come from?
Arises from squamous epithelial remnants of Rathke’s pouch (base of the brain near the pituitary).
benign tumours
what could pituitary mass lesions be?
-Non-Functioning Pituitary Adenomas (silent)
-Endocrine active pituitary adenomas
-Malignant pituitary tumors: Functional and non-functional pituitary carcinoma
-Metastases in the pituitary (breast, lung, stomach, kidney)
-Pituitary cysts: Rathke’s cleft cyst, Mucocoeles, Others
what is rathke’s cyst derived from?
remnants of rathke’s pouch
what is rathkes pouch?
an evagination at the roof of the developing mouth in front of the buccopharyngeal membrane
what does rathkes pouch give rise to?
gives rise to the anterior pituitary.
describe the structure of rathkes pouch
Benign tumour infiltrates surrounding structures
Solid, cystic, extends to suprasellar region
what symptoms does rathkes pouch cause?
Visual disturbances, growth failure, pituitary hormone deficiency
what symptoms does rathke’s cyst cause?
Mostly asymptomatic and small
Present with headache and amenorrhoea (missed menstruation), hypopituitarism and hydrocephalus (build-up of fluid on the brain)
what is a meningioma ?
the commonest tumour of region after pituitary adenoma
what is a meningioma a complication of?
radiotherapy
what symptoms is meningioma associated with?
Visual disturbance and endocrine dysfunction
- Usually present with loss of visual acuity, endocrine dysfunction and visual field defects
what percentage do pituitary adenomas account for of primary inter cranial tumours?
14-28%
what percentage do non functioning pituitary adenomas account for of clinically relevant pituitary adenomas?
<10-15%
what is the percentage of macroadenomas that get headaches and visual disturbances?
50% of macroadenomas have visual disturbances and 50% have headaches
what are the signs of aggressiveness?
Large size
Cavernous sinus invasion
Lobulated suprasellar margins
what are the three types of pituitary dysfunction?
-tumour mass effects
-hormone excess
-hormone deficiency
what tests do you do to test for Non-functioning tumours?
No specific test but absence of hormone secretion
Test normal pituitary function
Trans-sphenoidal surgery if threatening eyesight or progressively increasing in size
what are the local mass effects?
Headaches
Cranial Nerve Palsy and Temporal Lobe Epilepsy
CSF rhinorrhoea
Visual Field Defects
why is testing pituitary function complex?
-Many hormones: GH, LH/FSH, ACTH, TSH and ADH
-May have deficiency of one or all and may be borderline
-Circadian rhythms and pulsatile
what is the guiding principle of testing pituitary function?
If the peripheral target organ is working normally the pituitary is working
when testing for primary thyroid, what should you find?
Raised TSH low Ft4
when testing for hypopituitary, what should you find?
Low Ft4 with normal or low TSH
when testing for graves disease ( toxic), what should you find?
Suppressed TSH high Ft4
when testing for TSHoma ( very rare) , what should you find?
High Ft4 with normal or high TSH
