Pituitary Pathology Flashcards
what is the anterior pituitary also known as
adenohypophysis
what is the anterior pituitary derived from
rathke’s pouch
what hormones does the anterior pituitary secrete
trophic: TSH, ACTH, FSH, LH
non-trophic: GH and Prolactin
what is the posterior pituitary also known as
neurohypophysis
what does the pituitary consist of
extension of neural tissue consists of modified glial cells and axonal processes
what hormones does the posterior pituitary secrete
ADH (vasopressin) and oxytocin
where are posterior pituitary hormones produced
hypothalamus
how are the cells in the pituitary arranged
in islands like other endocrine glands or arranged in clusters
are pituitary adenomas benign or malignant
benign
what cells are pituitary adenomas derived from
anterior pituitary cells
how common are pituitary adenomas
relatively common (10% intra-cranial tumours)
what syndrome is associated with pituitary adenomas
MEN1 (Wermer Syndrome)
pituitary adenomas are quite characteristic
what is significant about macro-adenomas (over 1cm)
can cause symptoms due to compression
how are pituitary adenomas classified
by the cell type/hormone produced
which is the most common pituitary adenoma
prolactinoma (30%)
what can be some symptoms of large adenomas and why
visual field defects (press on optic chiasma-bitemporal hemianopia), can cause pressure atrophy of surrounding normal tissue, infarction can. lead to panhypopituitarism
what is panhypopituitarism
lose all anterior pituitary, ischaemic necrosis along with tumour
what are some symptoms of a prolactinoma
infertility, lack of labido, amenorrhea (25%)
what is the second most common pituitary adenoma
growth hormone secreting
what can GH cause
increase in Insulin Like Growth Factor (IGF)
what happens in growth hormone pituitary adenoma
stimulation of growth of bone, cartilage and connective tissue
what are some symptoms of growth hormone pituitary adenoma
giantism or acromegaly
what does ACTH secreting pituitary adenomas cause
cushings, bilateral adrenocortical hyperplasia
how common are pituitary carcinomas
rare (less than 1%)
are pituitary carcinomas usually functional or non-functional
functional (prolactin or ACTH)
how is pituitary hypofunction usually presented
non-specifically related to all anterior hormones (panhypopituitarism)
where is a craniopharyngioma derived from
Rathke’s pouch
what percentage of intracranial tumours are craniopharyngiomas
1-5%
what are some characteristics of a craniopharyngioma
slow growing, often cystic and may calcify
do craniopharyngiomas usually arise within the sella or suprasellar
suprasellar
what are the bimodal incidences of craniopharyngiomas
5-15 and 6th-7th decade of life
what are some symptoms of a craniopharyngioma
headaches and visual disturbances (children might have growth retardation)
how good is the prognosis of a craniopharyngioma
excellent especially if under 5cm
what can happen following radiation in the context of a craniopharyngioma
SCC
how are posterior pituitary syndromes diagnosed
biochemical and physiological diagnostic process
what are the 2 posterior pituitary syndromes
diabetes insipidus and SIADH secretion
what are the 2 types of diabetes insipidus
central and nephrogenic
what causes central diabetes insipidus
ADH deficiency
trauma (inc surgery), tumours and inflammatory disorders of hypothalamus and pituitary
what causes nephrogenic diabetes insipidus
renal resistance to ADH effects
what causes SIADH secretion
ectopic production of ADH-paraneoplastic syndrome
