20. Pituitary and Thyroid Pathology Flashcards
What is the anterior lobe of the pituitary also known as?
Adenohypophysis
Where does the anterior lobe of the pituitary originate from?
Rathke’s pouch
What is the other name for the posterior lobe of the pituitary?
Neurohypophysis
Where does the posterior lobe originate from?
3rd ventricle
What is pseudohypofunction of an endocrine organ?
Target organ receptors not functioning
Which hormones increase the release of:
a. GH
b. TSH
c. FSH and LH
d. ACTH
a. GHRH
b. TRH
c. GnRH
d. CRH
Which hormones inhibit the release of:
a. Prolactin
b. GH
a. Dopamine
b. Somatostatin
What is the most common tumour of the pituitary?
Prolactinoma
What are the effects of the mass of a pituitary tumour?
Compress optic chiasm causing bitemporal hemianopia
Decrease in other hormones
Rarely symptoms of ICP
What are the symptoms of a prolactinoma in men?
Asymptomatic
Low libido
Impotence
What are the symptoms of a prolactinoma in women?
Amenorrhoea
Sterility
Galactorrhoea
Why does pituitary stalk compression cause increased prolactin release?
No inhibition by dopamine and PRL has no stimulatory hormone
What is the treatment for a prolactinoma?
Dopamine agonist
Surgery
What are the effects of high growth hormone on the structure of the adult body?
Prognathism Brow protrusion Broad nose Large hands and feet Enlarged tongue
What are the non-structural effects of acromegaly?
Carpal tunnel syndrome
Diabetes
Joint pain
Deafness
What is the difference between Cushing’s syndrome and Cushing’s disease?
Syndrome is high cortisol due to any cause
Cushing’s disease is due to an ACTH releasing adenoma
What are the causes of hypopituitarism?
Adenoma compressing other segments
Trauma
Post surgery or radiation
Ischaemic necrosis
What is Sheehan’s syndrome?
Ischaemic necrosis of the pituitary due to blood loss in childbirth
What does SIADH result in?
Excessive water resorption and volume overload
Hyponatraemia
What is diabetes insipidus?
Reduced secretion of ADH so that the kidneys can’t resorb water
What is measured in a TFT?
T4, T3
TSH
Thyroid antibodies
Thyroglobulin
What does euthyroid mean?
Normal thyroid function
What is a struma ovarii?
Ovarian teratoma secreting thyroid hormones
What are the primary causes of hyperthyroidism?
Grave’s disease
Multinodular goitre
Adenoma>carcinoma
What causes secondary hyperthyroidism?
TSH releasing pituitary adenoma
What is a ‘thyroid storm’?
Abrupt severe hyperthyroidism a/w underlying Grave’s
Can cause atrial fib
What are the causes of primary hypothyroidism?
Hashimoto thyroiditis
Iatrogenic: surgery, radioactive iodine, drugs
Iodine deficiency
Dyshormogenic goitre: congenital
What affect can hypothyroidism have on the heart?
Complete heart block
What is Grave’s disease?
Familial autoimmune condition
IgG autoantibody to TSH receptor: stimulatory effects
What are the microscopic signs of Grave’s disease?
Star shaped follicles
Little coloid
Lymphocytes
What are the clinical signs of Grave’s disease?
Hyperthyroidism +/- swelling
Exophthalmos
Pretibial myxedema
What is Hashimoto’s disease?
Autoimmune syndrome causing hypothyroidism
Follicular epithelial cells are attacked by killer T cells
What can cause hyperthyroidism in Hashimoto’s disease?
Briefly due to inflammatory reaction causing release of all T3 and T4
What is the macroscopic appearance of the thyroid in Hasmimoto’s disease?
Swollen gland at start, later atrophies
What is the microscopic appearance in Hashimoto’s disease?
Dense infiltrate
Oxyphilic change of follicular epithelium
What is De Quervain’s thyroiditis?
Subacute granulomatous thyroiditis
History of URTI before onset of sudden painful enlargement of the thyroid and fever
How long does De Quervain’s thyroiditis last?
6-8 weeks, after which the patient returns to normal
What is the microscopic appearance of De Quervain’s thyroiditis?
Focal acute inflammation
Granulomas
What investigations should be done into a thyroid nodule?
Ultrasound
Radionuclide imaging (warm vs cold)
FNA biopsy
What thyroid nodules are concerning?
Solitary
Young or male patient
Cold on radionuclide imaging
What is a thy 1 stage on an FNA and what is the management?
Non diagnostic
Repeat FNA
What is a thy 2 stage on an FNA and what is the management?
Non-neoplastic: hyperplastic or colloid nodule
No need to intervene
What is a thy 3 stage on an FNA and what is the management?
Possible neoplasm:
3f: follicular lesion
3a: atypia
Taken out
What is a thy 4 or 5 stage on an FNA and what is the management?
4: suspicious of malignancy
5: certain of malignancy
Remove
What are the features of a follicular adenoma?
Euthyroid or sometimes hyperthyroid
Encapsulated, firm and small
NO INVASION
What are the risks for malignant thyroid tumours?
Radiation
High iodine
Genetic
Nodules
What is the most common malignant thyroid tumour?
Papillary carcinoma
What patient group are papillary carcinomas most common in and what is the prognosis?
20-40 y/o females
Low grade tumour with very good prognosis
What are the microscopic features of papillary carcinomas?
Pale, overlapping nuclei
Nuclear inclusions and grooves
Psammoma bodies
Which malignant thyroid tumour is associated with a slowly enlarging, painless nodule?
Follicular carcinoma
What is the treatment for a follicular carcinoma?
Total thyroidectomy
Radioactive iodine
Which thyroid tumour is associated with MEN syndromes?
Medullary carcinoma
What hormone is secreted by medullary carcinomas?
Calcitonin
What is distinctive about the stroma of a medullary carcinoma?
Amyloid-like: stains with congo red
Which thyroid tumour has the worst prognosis?
Anaplastic carcinoma
