pituitary and adrenal pathology Flashcards
describe the anterior pituitary gland
Adenohypophysis
Derived from Rathke’s pouch
Secretes trophic and non-trophic hormones
Trophic: TSH, ACTH, FSH, LH
Non-trophic: GH and Prolactin
describe the posterior pituitary gland
Neurohypophysis
Extension of neural tissue consists of modified glial cells and axonal processes
Secretes ADH (vasopressin) and oxytocin
what are the pathologies of anterior pituitary hyperfunction?
adenoma
carcinoma
what are the pathologies of anterior pituitary hypofunction?
Surgery/radiation
Sudden Haemorrhage into gland
Ischaemic necrosis
Sheehan Syndrome
Tumours extending into sella
Inflammatory conditions (Sarcoidosis)
what are the pathologies of the posterior pituitary?
Posterior Pituitary
Diabetes Insipidus
Lack of ADH secretion
Can lead to life threatening dehydration
Syndrome of Inappropriate ADH secretion (SIADH)
Ectopic secretion of ADH by tumours
Primary disorder in the pituitary
what are the most common functional pituitary adenomas?
prolactinoma - Infertility, lack of libido, amenorrhea
growth hormone secreting - increase in insulin-like growth factors, stimulates growth of bone, cartilage and connective tissue, causes gigantism or acromegaly
ACTH secreting - cushing’s disease, usually micro adenoma, bilateral adrenocortical hyperplasia
describe craniopharyngioma
Derived from remnants of Rathke’s pouch
1 – 5% of intracranial tumours
Slow growing, often cystic, may calcify
Some arise within the sella but most suprasellar
good prognosis
what are the symptoms of craniopharyngioma?
headaches and visual disturbances (children may have growth retardation)
describe the adrenal gland
Bilateral Glands ~ 4 - 5 grams each
Sit superior and medial to upper pole of kidneys
Composed of an outer cortex and a central medulla
what are the 3 zones of the adrenal gland cortex?
Zona Glomerulosa –
Mineralocorticoids
Aldosterone
Zona Fasciculata –
Glucocorticoids
Cortisol
Zona Reticularis –
Sex Steroids + Glucocorticoids
GFR
describe the medulla of the adrenal gland
Central core of the adrenal – distinct from the cortex
Innervated by pre-synaptic fibres from sympathetic nervous system
Neuroendocrine (chromaffin) cells - secrete catecholamines
what is the usual presentation of adrenocortical tumours?
Incidental finding (radiology, autopsy)
Hormonal effects
Mass lesion
Carcinomas with necrosis can cause fever
describe adrenocortical adenoma
Well circumscribed, encapsulated lesions
Usually small – up to 2 to 3cm
Yellow / yellow brown cut surface (lipid)
Composed of cells resembling adrenocortical cells
Well differentiated, small nuclei, rare mitoses
Can be functional, but more likely not
describe adrenocortical carcinoma
Rare
More likely to be functional - virilising tumours usually malignant
Can closely resemble adenoma
how do adrenocortical carcinomas spread?
Local invasion – retroperitoneum, kidney
Metastasis – usually vascular (liver, lung and bone)
Peritoneum and pleura
Regional lymph nodes
poor prognosis- 5 year survival rate 20-35%
what features are suggestive of adrenocortical carcinoma?
Large size (>50g, often >20cm)
Haemorrhage and necrosis
Frequent mitoses, atypical mitoses
Lack of clear cells
Capsular or vascular invasion
describe primary hyperaldosteronism
Conn’s syndrome
Usually associated with diffuse or nodular hyperplasia of both adrenal glands
35% have adenoma, rarely carcinoma
glucocorticoid remediable
describe secondary hyperaldosteronism
Increased renin
Decreased renal perfusion, hypovolaemia, pregnancy
describe hypercortisolism
Cushing’s syndrome or disease
Exogenous or endogenous
Exogenous – iatrogenic (steroid therapy)
Endogenous-
ACTH dependent- ACTH secreting pituitary adenoma (70%) - Cushing’s disease
Ectopic ACTH (10%) - Small cell lung cancer
Gives rise to adrenal hyperplasia
ACTH independent
Adrenal adenoma (10%) or carcinoma (5%)
Non-lesional adrenal gland atrophies
describe secondary adrenocortical hypofunction
Failure to stimulate adrenal cortex
Hypothalamic-pituitary disorder
Hypopituitarism
Suppression of adrenal cortex
Treatment with steroids
describe primary adrenocortical hypofunction
can be acute or chronic and has many causes
describe acute primary adrenocortical insufficiency
Rapid withdrawal of steroid treatment
Crisis in patient’s with chronic adrenocortical insufficiency – due to stress e.g. infection or not increasing dose of steroid treatment
Massive adrenal haemorrhage - Newborn, Anticoagulant treatment, DIC, Septiceamic infection – Waterhouse Friderichsen
describe chronic primary adrenocortical insufficiency (addison’s disease)
-addison’s disease
-3 common causes - infection, metastatic malignancy, autoimmune adrenalitis
-shows signs once >90% of gland is destroyed
when does addison’s disease manifest itself?
manifests once there are significant decreases in glucocorticoid and mineralocorticoid levels
what are the symptoms of addison’s disease?
vague-
-weakness, fatigue, anorexia, weight loss, vomiting, diarrhoea
-pigmentation (not seen in hypopituitarism)
what are the 2 main types of adrenal medullary tumours?
phaeochromocytoma & neuroblastoma
describe adrenal medullary neuroblastoma
Composed of primitive appearing cells but can show maturation and differentiation towards ganglion cells
Age and stage important for prognosis
Amplification of N-myc & expression of telomerase predict a poor outcome
describe phaeochromocytoma
A neoplasm derived from chromaffin cells of the adrenal medulla
Secrete catecholamines
Rare cause of secondary hypertension
what are the effects phaeochromocytoma can cause?
hypertension-paroxysmal episodes
complications- cardiac failure, infarction, arrhythmias
what are the 10%s of phaeochromocytoma?
10% are extra adrenal
10% are bilateral
10% are biologically malignant
10% are not associated with hypertension
(25% are familial)
what is the average size of a phaeochromocytoma?
100g (can range from 1g to >2kg)
what genetic condition is phaeochromocytoma associated with?
multiple endocrine neoplasia type 2 (men2)
what is the treatmnet of phaeochromocytoma?
surgery- prepare for surgery by
full alpha and beta blockade.
alpha first using a-blockers phenoxybenzamide
then beta using b-blockers e.g. propanolol
fluid and/ or blood replacement
careful anaesthetic asessment
how do you diagnose phaeochromocytoma?
identify catecholamine excess
MRI abdomen, full body
PET scan
