53 - Diseases of the endocrine system Flashcards
Pituitary gland - features
Situated in Sella Turcica beneath hypothalamus
Ant part (75%) - outpouching of oral cavity
Post part (25%) down growth of hypothalamus
Ant. pit. hypofunction
Tumours - non-sec adenoma, metastatic carcinoma
Trauma
Infarction
Inflammation - granulomatous, autoimmune, other infections
Iatrogenic
1° pituitary tumours
Most are adenomas + benign
Derived from any hormone producing cell
Functional clinical effect 2° to hormone being produced
Local effects due to pressure on optic chiasma or adjacent pituitary
Types of pit adenoma
Prolactinoma (most common) - galactorrhoea and menstrual disturbance
Growth hormone secretion - gigantism in children. acromegaly in adults
ACTH secreting - Cushing’s syndrome
Thyroid anatomy
Bilobed joined by isthmus
Thin fibrous capsule
C5,6,7
Thyroid embryology
Main part migrates from foregut to ant. neck (remnant is foramen caecum at junction 2/3 and post 1/3 of tongue
Ectopia and heterotopia
Lingual thyroid - most common at base of tongue
>75% of patients with this are asymptomatic.
The others have hypothyroid and 10% of these cretinism
Thyroglossal duct cyst
Persistent track representing the embryological migratory path of thyroid anlage of the ant. neck
7% of adults
Asymptomatic midline neck mass
Acute thyroiditis
Acute inflammation of the thyroid parenchyma associated with local/systemic infection
Generalised sepsis
Fever, chills, malaise, pain, swelling of ant. neck
Palpation thyroiditis
Microscopic granulomatous foci centred on thyroid follicles
2° to rupture of thyroid follicles due to palpation or surgery
Patients almost always have a thyroid nodule
Riedel thyroiditis
Rare fibrosing form of chronic thyroiditis
Fibrosing disorder may also affect retroperitoneum, lung, mediastinum, biliary tree, pancreas, kidney, subcutis.
Present with firm goitre
Symptoms inc. dysphagia, hoarseness, stridor.
Mistaken for malignant neoplasm
Benign self-limited disease
Chronic lymphocytic thyroiditis (Hashimoto’s) - what is it?
Autoimmune chronic inflammatory disorder associated with diffuse enlargement and thyroid autoantibodies
Chronic lymphocytic thyroiditis (Hashimoto’s) - risk factors
Female>male Peak age = 59 Diffusely enlarged non-tender gland Serum thyroid antibodies elevated Lymphocytic infiltration of thyroid parenchyma, often with germinal centre formation Causes hypothyroid 80-fold risk of thyroid lymphoma Increased risk of papillary carcinoma of the thyroid
Diffuse hyperplasia (Grave’s) - what is it?
Autoimmune process results in clinical hypothyroidism and diffuse hyperplasia of the follicular epithelium
Diffuse hyperplasia (Grave’s) - epidemiology
1% worldwide Female>male Peak in third and fourth decades 80% of hypothyroidism cases Symptoms of hyperthyroidism Thyroid diffusely enlarged T3 and T4 elevated w/ TSH suppressed Thyroid autoantibodies especially TSH Ig May develop permanent hypothyroidism
Diffuse hyperplasia (Grave’s) - clinical presentation
Pretibial myxoedema, hair loss, wide-eyed stare or proptosis, tachycardia, hyperactive reflexes
Multinodular goitre
Enlargement of thyroid with varying degrees of nodularity
Most patients are euthyroid
Dominant nodule may be mistaken clinically for thyroid carcinoma
Tracheal compression or dysphagia may develop with large nodules
Follicular adenoma
Benign encapsulated tumour with evidence of follicular cell differentiation
F>M Wide age range - 50,60 Painless neck mass for years Solitary nodule involved one lobe Usually cold nodule on radioactive iodine imaging
Papillary carcinoma - who? prevalence?
commonest type of tyroid carcinoma
F>M
43 yo mean
Papillary carcinoma - risk factors
Familial autosomal dominant non-medullary thyroid carcinoma FAP Cowden's syndrome Therapeutic radiation Radiation exposure
Papillary carcinoma - pathogenesis
Activation of RET or NTRK1
Variety of chromosomal translocations or inversions
BRAF V600E
RAS mutations
Papillary carcinoma - macroscopic appearance
Ill defined Infiltrative Some encapsulated May be cystic Granular
Follicular neoplasms - types
Follicular adenoma
Minimally invasive follicular carcinoma
Widely invasive follicular carcinoma
Hurthle cell neoplasm
Follicular carcinoma - %%%
10-20% of all thyroid cancers
90% present with solitary nodule in thyroid
Minimally invasive = 5% mets
Widely invasive = 60% mets
Follicular neoplasms - minimal vs widely invasive
min: completely encapsulated, invasion only detectable histologically
wide: macroscopic evidence of invasion. Widespread invasion histologically. Minimally invasive but tumour invades >4 capsular blood vessels.
Hurthle cell carcinoma - what is it?
Recognised large acidophilic cells in canine thyroid
Parafollicular or C cells
Hurthle cell carcinoma - who?
3% of all differentiated thyroid carcinomas
Med age: 53 (24 -85yo tho)
Sex F:M, 7:3
Hurthle cell carcinoma - clinical behaviour
Significant incidence of lymph node mets
Common haemato spread to bone, liver and lung
Insular carcinoma - who?
Elderly patients of mean age 58
Insular carcinoma - mets?
Lymph node and distant mets in up to 50%
up to 60% will die
Anaplastic carcinoma - who?
Older patients
Mean age 65
Anaplastic carcinoma - clinical presentation
Longstanding history of goitre
Usually inoperable
Anaplastic carcinoma - prognosis
Median survival is months
Medullary carcinoma - what is it?
Malignant tumour showing differentiation to parafollicular C cells
Medullary carcinoma - genetic basis
70-80% are sporadic 20-30% are AD MEN2a and B Familial MTC Mutations in RET gene
Primary thyroid lymphoma - what is it?
Primary lymphoma arising within thyroid gland often associated with lymphocytic thyroiditis
Primary thyroid lymphoma - who?
2% of thyroid neoplasms
Mean age 70
Primary thyroid lymphoma - clinical presentation
Mass in thyroid
Rapid enlargement
Pain
Dysphagia
Associated cervical lymphadenopathy
Primary thyroid lymphoma - prognosis
Dependent on histology + stage
60% survival
Where do thyroid tumours met to?
Renal cell carcinoma Melanoma Small cell lung cancer Neuroendocrine carcinoma Breast cancer
Primary hyperparathyroidism definition
Excessive section of PTH from one of more glands
Secondary hyperparathyroidism
Hyperplasia of glands with elevated PTH in response to hypocalcaemia
Renal insufficiency, malabsorption, vit D deficiency
Tertiary hyperparathyroidism
Adenoma in association with longstanding secondary hyperparathyroidism
Primary hyperparathyroidism - pathogenesis
Ageing
Ionising radiation
MEN 2a
Primary hyperparathyroidism - types
Single adenoma (85%)
Diffuse chief or clear cell hyperplasia (10%)
Carcinoma (5%)
Primary chief cell hyperplasia - definition
Non-neoplastic increase in parathyroid parenchymal cell mass within all parathyroid tissue w/o a known stimulus
Primary chief cell hyperplasia - who?
17 per 1,000,000
Peak age = 50-70 yo
Primary chief cell hyperplasia - symptoms
Fatigue, lethargy, anorexia, weakness, vomiting, bones, stones and ab moans
Elevated calcium, low phosphorous high parahormone
Primary chief cell hyperplasia - treatment
surgery
Parathyroid adenoma - what is it?
Encapsulated benign neoplasm of parathyroid cells
Parathyroid adenoma - who?
1 per 1,000
Parathyroid adenoma - symptoms
Hypercalcaemia
Parathyroid adenoma - risk factors
MEN1 and MEN2 and hyperparathyroidism and jaw tumour syndrome
Parathyroid adenoma - clinical presentation
Single enlarged parathyroid gland, remaining gland suppressed and small
Parathyroid carcinoma - what is it?
Malignant tumour derived from parathyroid parenchymal cells
Parathyroid carcinoma - prevalence
5% of primary hyperparathyroids
Parathyroid carcinoma - symptoms
Hypercalcaemia
Parathyroid carcinoma - prognosis
50% 10 year survival rate
Parathyroid carcinoma - treatment
Surgery
Adrenal congenital hypoplasia - what is it?
Reduced volume of adrenocortical tissue leading to adrenal cortical insufficiency
Adrenal congenital hypoplasia - prevalence?
Rare
Adrenal congenital hypoplasia - risk factors
Family
Adrenal congenital hypoplasia - prognosis
poor if untreated
Adrenal congenital hypoplasia - who?
Male predominance often XL
Adrenal congenital hypoplasia - clinical presentation
Hypoadrenalism
Adrenal congenital hypoplasia - used to be fatal now treatment is…
Glucocorticoid and mineralocorticoid replacement
Congenital adrenal hyperplasia - what is it?
Inherited disorder caused by deficiency of enzymes req. for synthesis of glucocorticoids and mineralocorticoids
Congenital adrenal hyperplasia - pathogenesis
21 hydroxylase deficiency accounts for more than 90%
Congenital adrenal hyperplasia - clinical presentation
Deficiencies of cortical and aldosterone secretion
Genital abnormality in females, nomral in males
Virilisation and hyperandrogenism
Advanced bone growth with premature epiphyseal maturation leading to short adult stature
Addison’s disease - what is it?
Primary adrenal cortical insufficiency caused by adrenal dysgenesis, adrenal destruction
Addison’s disease - who?
5.3 per million pop
High mortality if not diagnosed
Addison’s disease - pathogenesis
Autoimmune form most common
TB more in developing world
Addison’s disease - clinical presentation
hyperpigmentation, postural hypotension and hyponatraemia
Addison’s disease - treatment
Long term steroid replacement
Adrenal cortical nodule - what is it?
Benign non-functional nodules of adrenal cortex
Adrenal cortical nodule - who?
1.5 and 3% of population
Elderly, hypotensive and diabetic
Adrenal cortical nodule - how often diagnosed?
Incidental on radiograph
Adrenal cortical nodule - treatment
none required
Adrenal cortical adenoma - what is it?
Benign neoplastic proliferation of adrenal cortical tissue
Adrenal cortical adenoma - incidence
1-5% of pop
Adrenal cortical adenoma - symptoms related to endocrine hyperfunction
Hypertension
Cushing’s
Virilisation
Adrenal cortical adenoma - what do they release sometimes? what does this cause?
Aldosterone-producing tumours can cause Conn’s syndrome
Cortisol-producing reduce Cushing’s syndrome
Rare tumours cause virilisation
Adrenal cortical adenoma - look like
Unilateral solitary masses
Average size 2cm
Well-circumscribed yellow/brown nodules
Adrenal cortical carcinoma - what is it?
Malignant counterpart of adrenal adenoma
Adrenal cortical carcinoma - who?
3% of endocrine neoplasms
1 per million pop
Adrenal cortical carcinoma - symptoms
Hormone excess
Ab mass
Adrenal cortical carcinoma - prognosis
age, stage
5yr = 70%
Phaeochromocytoma - what is it?
Catecholamine-secreting tumour arising from adrenal medulla
Phaeochromocytoma - who?
8 per million
Phaeochromocytoma - pathogenesis
Most sporadic but familial = MEN2a and 2b von recklinghausen’s disease and von hippel-lindau disease symptoms of hypertensions, palpitations, headaches and anxiety.
Phaeochromocytoma - tests
elevated urine catecholamines, adrenaline, noradrenaline
Phaeochromocytoma - prognosis
excellent when benign and surgically managed
