Pathology of the pituitary and adrenal glands Flashcards
What bony area does the pituitary lie within?
sella turcica
What trophic hormones does the anterior pituitary release?
TSH; ACTH; FSH; LH
What non-trophic hormones does the anterior pituitary release?
GH and prolactin
What does the posterior pituitary consist of?
modified glial cells and axonal processes- extension of neural tissue. non-myelinated axons of neurosecretory neurons
What are the 2 types of cell found in the anterior pituitary?
acidophils and basophils
What are the reasosn for hypofunction of the anterior pituitary?
surgery-radiation; sudden haemorrhage into gland; ischaemic necrosis; tumours extended into sella; inflammatory conditions
What is Sheehan syndrome?
postpartum hypopituitarism restulting from ischaemic necrosis due to blood loss and hypovolaemic shock during childbirth
What is the most common functional type of pituitary adenoma?
prolactinoma
What symptoms occur with a prolactinoma?
infertility; lack of libido; amenorrhea
What is the second most commmon functional pituitary adenoma?
growth hormone secreting
What happens with a growht hormone secreting adenoma?
growth of bone; cartilage and connective tissue is stimulating causing gigantism or acromegaly
What does an ACTH secreting adenoma cause?
Cushing’s disease
What type of pituitary hypofunction usually occurs?
panhypopituitarism
What is a craniopharyngioma derived from?
remnants of Rathke’s pouch
What ar ethe features of a craniopharyngioma?
slow growing
often cystic
may calcify
What are the symtpoms of craniopharyngioma?
headaches and visual disturbances
What are hte 2 types of diabetes insipidus?
central or nephrogenic
what happens with nephrogenic diabetes insipidus?
renal resistance to ADH effects
What are the causes of central diabetes insipidus?
trauma; tumours and inflammatory disorders of hypothalamus and pituitary
What are the causes of adrenocortical hyperfunction?
hyperplasia; adenoma; carcinoma
What are the causes of adrenocortical hypofunction?
acute- waterhouse-friderichsen; chronic- Addison’s
What is the primary problem in congenital adrenocortical hyperplasia?
deficiency/lack of enzyme required for steroid biosynthesis
what does a lack of enzyme for steroid biosynthesis result in?
increased androgen production; reduced cortisol stimulates ACTH release and cortical hyperplasisa
What are the symptoms of increased androgen production?
masculinisation; precocious puberty
What are the causes of acquired adrenocortical hyperplasia?
excess ACTH production; bilateral adrenal enlargement; diffuse or nodular
What cancer typically ectopically produces ACTH as part of its paraneoplastic syndrome?
small cell lung carcinoma
What is the difference between diffuse and nodular hyperplasia?
diffuse-ACTH driven wherease nodular is usually ACTH independent
What causes fever with a cancer?
when the carcinoma necroses
What are the features of an adrenocortical adenoma?
well circumscribed, encapsulated lesions; small. composed of cells resembling adrenocortical cells; well differentiated, small nuclei, rare mitoses
What is the general difference between adrenocortical carcinoma and adenoma?
carcinoma are much rare and more likely to be functional
What are the features suggesting that the tumour is more likely to be a carcinoma than adenoma?
large size; haemorrhage and necrosis; frequent mitoses; atypical mitoses; lack of clear cells; capsular or vascular invasion
What is primary hyperaldosteroniism called?
Conn’s syndrome
What causes Conn’s syndrome?
diffuse or nodular hyperplasia of both adrenal glands; adenoma
What is hypercortisolism called?
Cushing’s syndrome or disease
What are the causes of ACTH dependent hypercortisolism?
ACTH secreting pituitary adenoma (Cushing’s disease); ectopic ACTH- small cell lung cancer
What are the causes of ACTH independent hypercortisolism?
adrenal adenoma or carcinoma; non-lesional adrenal gland
what are the causes of secondary adrenocortical hypofunction?
failure to stimulate the adrenal cortex eg hypopituitarism or suppression of adrenal cortex eg Tx with steroids
What are the causes of acute primary adrenocortical insufficiency?
rapid withdrawal of steroid Tx; crissis in pt with chronic adrenocortical insufficiency due to stress; massive adrenal haemorrhage
What are the 3 common causes of Addison’s disease?
autoimmune adrenalitis; infectious; metastatic malignancy
How much of the gland needs to be destroyed before a pt gets symptoms of adrenocortical insufficiency?
more than 90%
What are the uncommon causes of Addison’s ?
amyloid; sarcoidosis; haemochromatosis
What are the symptoms of Addison’s disease?
weakness; fatigue; anorexia; nausa; vomiting; wt loss; diarrhoea; pigmentation; hyperkalaemial hyponatraemia; volume depletion and hypotension; hypoglycaemia
What innervates the medulla?
pre-synpatic fibres from sympathietic nervous system
What cells secrete catecholamines?
chromaffin cells
What are the types of adrenal medullary tumours?
phaeochromocytoma; neuroblastoma
How old are patients usually when diagnosed with a neuroblastoma?
within 18 months
Where do neuroblastoma usually arise?
in the adrenal medulla (40%), the rest mostly along the sympathic chain
What type of cells make up a neuroblastoma?
primitive appearing cells but can show maturation and differentiation towards ganglion cells
What can trigger paroxysmal episode of hypertension in phaemochromocytoma?
stress; exercise; posture; palpation of tumour
What are the complications of phaemochromocytoma?
cardiac failure; infarction; arrhythmias; CVA
How is phaeochromocytoma diagnosed?
detection of urinary excretion of catecholamines and metabolites
What are the extra-adrenal phaeochromocytomas called?
paragangliomas
Why are phaeochromocytomas called the 10% tumour?
10% are extra-adrenal; 10% are bilateral; 10% are bioloigcally malignant; 10% are not associated with HT: 10% occur in children
How many cases of phaeochromocytoma are familial?
25%
What will turn a phaeochromocytoma dark brown?
potassium dichromate due to oxidation of catecholamines in tumour cells
Where do phaeochromocytomas tend to metastasise?
bone; regional lymph nodes; liver; lung
What multiple endocrine neoplasia syndromes is phaeochromocytoma a feature of ?
MEN2A and MEN2B
What else is seen with MEN2A?
medullary thryoid carcinoma; parathyroid hyperplasia
What else is seen with MEN2B?
medullary thyroid carcinoma; neuromas or ganglioneuromas; marfanoid habitus
What are the 3 zones of the adrenal cortex?
zona glomerulosa; zona fasciculata; zona reticularis
What is produced in the zona glomerulosa?
mineralocorticoids- aldosterone
What is produced in the zona fasciculata?
glucocorticoids-cortisol
What is produced in the zona reticularis?
sex steroids and glucocorticoids
