Pathology of the Pituitary and Adrenal Glands Flashcards
what is the anterior pituitary also known as and where does it come from?
adenohypophysis
derived from Rathkes pouch
what type of hormones does the anterior pituitary secrete>
trophic = TSH, ACTH, FSH, LH non-trophic = GH and prolactin
what is the posterior pituitary also known as and where does it come from?
neurohypophysis
extension of neural tissue consists of modified glial cells and axonal processes
what cells are present in the anterior pituitary?
islands, cords of cells acidophils - somatotrophs (GH) - mammotrophs (prolactin) basophils - corticotrophs (ACTH) - thyrotrophs (TSH) - gonadotrophs (FSH/LH) chromophobes
what cells are present in the posterior pituitary?
non-myelinated axons of neurosecretory neurons
what anterior pituitary pathology can cause hyperfunction?
adenoma
carcinoma
what anterior pituitary pathology can cause hypofunction?
surgery/radiation sudden haemorrhage into gland ischaemic necrosis (sheehan syndrome) tumours extending into sella inflammatory conditions (sarcoidosis)
what posterior pituitary pathology can cause decreased ADH secretion?
diabetes insipidus
what posterior pituitary pathology can cause increased ADH secretion?
SIADH
- ectopic secretion of ADH by tumours
- primary disorder in pituitary
what is a pituitary adenoma and what causes it?
tumour derived from cells of anterior pituitary
can be sporadic or associated with MEN1 gene (wermer syndrome)
what are the possible complications of a large adenoma?
visual field defects
atrophy of surrounding normal tissue
infarction leading to panhypopituitarism
classification of pituitary adenoma?
by cell type/hormone produced prolactin ACTH FSH/LH GH
name 3 functional pituitary adenomas
prolactinoma (most common)
growth hormone secreting (2nd most common)
ACTH secreting (cushings)
possible features of functional pituitary adenomas?
prolactinoma = infertility, amenorrhoea, lack of libido
GH secreting = bone, cartilage and connective tissue growth - gigantism/acromegaly
ACTH secreting = cushings
what usually causes pituitary hypofunction?
panhypopituitarism causes - granulomatous inflammation - sarcoidosis - infarction (shehans) - primary or metastatic tumours
what is craniopharyngioma?
tumour derived from remnants of rathkes pouch
slow growing, often cystic, can calcify, most are suprasellar
how do craniopharyngiomas present?
usually 5-15 yrs old or 60s-70s
headaches and visual disturbances
children may have growth retardation
excellent prognosis
name 2 syndromes of the posterior pituitary?
diabetes insipidus
SIADH secretion
- paraneoplastic syndrome of ectopic ADH production
what are the 2 types of diabetes insipidus?
central - ADH deficiency - trauma, tumours and inflammatory disorders of hypothalamus/pituitary nephrogenic - renal resistance to ADH effects
what are the 2 compartments of the adrenal gland?
outer cortex
central medulla
(capsule surrounds gland)
what other diseases may manifest as adrenal pathology?
pituitary disease (ACTH from functional adenoma)
Shock/DIC
any condition which destroys adrenal tissue
3 causes of adrenal hyperfunction?
hyperplasia
adenoma
carcinoma
2 types of adrenal hypofunction and what causes them?
acute
- waterhouse-friderichsen
chronic
- addisons disease
what causes congenital adrenocortical hyperplasia and what happens as a result?
group of autosomal recessive disorders causing deficiency/lack of enzyme required for steroid synthesis
altered synthesis leads to increased androgen production
reduced cortisol stimulates ACTH release and cortical hyperplasia
- can cause masculinisation or precocious puberty
what causes acquired adrenocortical hyperplasia and what happens?
endogenous ACTH production
- pituitary adenoma
- ectopic ACTH (paraneoplastic syndrome from small cell lung cancer)
causes bilateral enlargement of adrenal glands
- can be diffuse (ACTH dependant) or nodular (ACTH independent)
what is adrenogenital hyperplasia?
congenital adrenal hyperplasia
how does an adrenocortical tumour usually present?
mainly adults more males incidental finding (imaging etc) hormonal affects mass lesion carcinomas with necrosis can cause fever
describe adrenocortical adenoma?
well circumscribed, encapsulated lesion 2-3 cm yellow/yellow brown cut surface (lipid) cells resembling adrenocortical cells can be functional but usually not small nuclei, rare mitosis
describe an adrenocortical carcinoma
more likely to be functional, virilising tumours usually malignant
can resemble adenoma
spread
- local invasion
- metastases (usually vascular - liver etc)
- peritoneum and pleura
- regional lymph nodes
what features can help distinguish adrenocortical carcinoma from adenoma?
large size (often >20cm) haemorrhage and necrosis frequent/atypical mitosis lack of clear cells (still cytoplasm etc within the cells) capsular or vascular invasion
what are the two types of adrenocortical hypofunction?
primary (acute/chronic)
secondary
what causes secondary adrenocortical hypofunction?
failure to stimulate adrenal cortex (e.g hypopituitarism)
suppression of adrenal cortex (steroid therapy)
what causes acute primary adrenocortical insufficiency?
rapid withdrawal of steroid treatment
massive adrenal haemorrhage
crisis in patients with chronic adrenocortical insfficiency
what causes chronic adrenocortical insufficiency?
addisons disease autoimmune adrenalitis infections metastatic malignancy unusual causes (amyloid, sarcoidosis, haemochromatosis)
when do symptoms occur in chronic adrenocortical insufficiency?
once 90% of gland is destroyed
what are the symptoms of addisons disease?
insidious onset
weakness, fatigue, anorexia, nausea, vomiting, weight loss, diarrhoea
pigmentation (raised POMC)
what are the biological features of addisons disease?
decreased mineralocorticoids
- K+ retention, Na+ loss
- volume depletion and hypotension
hypoglycaemia
what can cause crisis in addisons disease?
stress - infection, trauma, surgery features - vomiting - abdo pain - hypotension - shock - death
describe the anatomical features of the adrenal medulla?
innervated by pre-synaptic fibres from sympathetic NS
neuroendocrine (chromaffin) cells secrete catecholamines
what tumours can occur in the adrenal medulla?
phaeochromocytoma
neuroblastoma
what is a neuroblastoma?
composed of primitive appearing cells but can show maturation and differentiation towards ganglion cells
40% in adrenal medulla, rest usually in sympathetic chain
diagnosed <18 months
what is a phaeochromocytoma?
neoplasm derived from chromaffin cells of the adrenal medulla
secrete catecholamines
rare cause of secondary hypertension
what are the features of phaemochromocytoma?
paroxysmal episodes of hypertension
- associated with stress, exercise, posture etc
complications
- cardiac failure, infarction, arrhythmias
- CVA
how is phaemochromocytoma diagnosed?
detection of urinary excretion of catecholamines and metabolites
“10% tumour”?
phaeochromocytoma 10% extra-adrenal 10% bilateral 10% malignant 10% not associated with hypertension 25% are familial
what does a phaeochromocytoma look like?
range from small to large (1g - 2Kg)
may see adrenal remnants on surface
yellow, red/brown to haemorrhagic and necrotic
K2Cr2O7 will turn tumour dark brown due to oxidation of catecholamines in tumour cells
benign vs malignant phaeochromocytoma?
malignant
- tend to be large and necrotic
- metastases = only definite evidence of malignancy
where is a phaeochromocytoma likely to metastasise?
skeletal
regional lymph nodes
liver
long
phaeochromocytoma is a feature of what other neoplastic disease?
multiple endocrine neoplasia
- MEN2A (sipple syndrome)
- MEN2B
