Pathology of the endocrine system Flashcards
Hyperplasia
increased number and secretory activity of cells
Atrophy
Diminution of cells due to lack of stimulation
How do we determine the cause of disease processes in endocrine glands?
morphological changes
biochemical measurements
Briefly describe the histology of the thyroid gland
follicles
colloid filled with thyroglobulin
epithelial cells
c - cells - secrete calcitonin
3 causes of primary hyperthyroidism
graves disease
toxic multinodular goitre
toxic adenoma
Graves disease antibodies
anti TSH receptor antibodies
thyroid peroxidase antibodies
Why is there eye involvement in graves disease?
ocular fibroblasts have TSH receptors
Describe the autoimmune destruction present in Hashimoto’s disease
destruction of thyroid epithelium
Tc cells, cytokine, antibody mediated destruction
circulating autoantibodies to thyroglobulin and TPO
What happens to the thyroid gland in Hashimoto’s thyroiditis?
diffuse enlargement and gradual failure
Hurthle cell change infiltrate and lymphocytes
Explain the pathway of multinodular goitre
iodine deficiency, goitrogens
impaired T3 and T4 synthesis
TSH is increased
repeated stimulation of the thyroid gland
hypertrophy and hyperplasia of the epithelium
Follicular adenoma of thyroid gland
most non-functioning
circumscribed, encapsulated
small micoradenomas found incidentally
Medullary carcinoma of thyroid gland
c cells - produces calcitonin
30% MEN 2A+B
prophylactic thyroidectomy
3 causes of parathyroid hyperfunction
primary hyperparathyroidism - asymptomatic hypercalcaemia
sporadic or familial - MEN 1 - mostly adenoma
secondary - in response to renal failure
Anterior pituitary histology and what is secreted by each cell type
acidophil = prolactin, GH
basophils - ACTH, TSH, LH, FSH
chromophobes
Most common cause of pituitary hyperfunction
pituitary adenoma
Pituitary adenoma
adults, MEN 1 - 5%
immunohistochemical stains to determine what hormone is being produced
Effect of a functioning pituitary adenoma
hormone excess
Effects of a functioning prolactinoma, GH secreting, ACTH secreting pituitary adenoma
galactorrhoea and menstruation disorders
acromegaly/gigantism
cushing’s disease
3 mass pressure effects of a large pituitary adenoma
increased ICP
visual fields
hypopituarism
How much of the pituitary gland needs to be lost to result in hypofunction?
75%
How can pituitary hypofunction result?
compressed by tumours eg craniopharyngioma
trauma
infection
post partum ischaemic necrosis
Hypercorisolism result in…
cushings syndrome
Hyperaldosteronism results in…
conns syndrome
causes of hypercortisolism
exogenous eg iatrogenic steroids
endogenous eg ACTH independent and dependent
Causes of acute and chronic adrenal insufficiency
acute - meningococcal septicaemia
chronic - Addison’s disease, infection, infarction, long term steroid use, atrophy, congenital
Causes of secondary adrenal insufficiency
pituitary failure
Adrenocortical adenoma
functioning = atrophy of adjacent cortex
non functioning
yellow-brown, circumscribed, 2-3cm, <30g
Adrenocortical carcinoma
rare, functioning
haemorrhage, necrosis, cystic
mets by lymph and blood - adrenal vein
spread from breast and lung cancer
Name an adrenomedullary tumour
phaeochroocytoma
Why does a phaeochromocytoma result in hypertension?
secrete catecholamines eg adrenaline
percentage association of phaechromocytoma and MEN-2?
30%
What are MEN disorders?
inherited disorders with underlying genetic mutations
What does MEN lead to?
hyperplasia/neoplasia at a younger age and multifocal
MEN 1
parathyroid, pancreatic and duodenal and pituitary prolactinoma
MEN 2
medullary carcinoma of thyroid
phaeochromocytoma
MEN 2A
parathyroid hyperplasia
MEN 2B
neuromas - aggressive, early age
