Pathology of the Thyroid Gland Flashcards Preview

Endocrine > Pathology of the Thyroid Gland > Flashcards

Flashcards in Pathology of the Thyroid Gland Deck (56):
1

What are the 4 main histological classifications of thyroid cancer?

Papillary - 6%
Follicular - 17%
Medullary - 3%
Anaplastic - 2%

2

What does differentiated thryoid cancer refer to?

Papillary and Follicular thryoid cancer

3

What do most DTCs do?

Take up iodine and secrete thyroglobulin - can act like normal thryoid cells
They are TSH driven

4

Decribe the rates of incidence of DTC in females and males.

Females - Rates increase from 15-40 then plateau
Males - Steady increase with age

5

How do DTC present?

Majority have palpable nodules
small % are chance findings
5% with local or disseminated mets

6

Give 5 points about Papillary thyroid cancer.

Associated with ionising radiation
Usually solitary nodule
Activates MAP kinase pathway
Spreads via lymphatics - lungs, bone, liver and brain
Associated with Hasimoto's thyroiditis

7

Give 4 points about Folicular thyroid cancer.

Associated with iodine deficiency
Usually single slow growing nodule - painless and non-functional
Mutations in PI3K/AKT pathway
Spreads haematogenously

8

What is the prognosis of DTC?

Generally good with 10 year mortality <5%

9

What Ix are used for suspected DTC?

USS guided FNA
Excision biopsy of lumh node

10

What are the clinical predictors of DTC?

New thyroid nodule 50 y.o
Nodule increased in size
Male
Lesion >4cm
History of head and neck irridation
Vocal cord palsy - do pre-operative laryngoscopy

11

What exactly is the best management option for DTC?

Sub total thyroidectomy with RAI

12

What risk stratification tool is used post op for patients with DTC and why is this used?

A - age
M - ets
E - extent of primary tumour
S - Size of primary tumour
Used to stratify pts as low or high risk

13

When and why is whole body iodine scanning used?

Pts who have had total or sub-total thyroidectomy
Given low dose iodine capsule which will be taken up by thyroid and any DTC cells in the body to see of tumour all removed or mets

14

If uptake at thyroid bed >0.1% of ingested activity, what does the patient undergo?

Thyroid remnant ablation
then whole body iodine scan repeated to ensure uptake in thyroid bed now <0.1%

15

What can be used as a tumour marker in DTC?

Thyroglobulin - produced by DTC cells and normal thyroid cells but 0 from them as removed

16

What is a follicular adenoma?

Discrete solitary mass derived from thyroid follicular cells encapsulated by a surrounding collagen cuff --> very well circumbscribed

17

Is a follicular adenoma functional or non-functional?

Usually non-functional but can secrete thyroid hormones

18

Can medullary thyroid cancers be familial?

Yes (bilateral/ mulitcentric) or sporadic (solitary nodule)

19

What are medullary thryoid cancers composed of?

Spindle or polygonal cells arranged in nest, trabeculae or follicles

20

What can medullary thyroid cancers cause?

dysphagia
hoarseness
airway compromise

21

Give 4 points about Anaplastic thyroid cancer.

Undifferentiated and aggressive tumours
Usually older patients
May occur in pts with a history of DTC
Rapid growth and involvement of neck structures and death

22

What is the Thy scale and why is it used?

Thy 1 - insufficient sample
Thy 2 - benign
Thy 3 - atypia probably benign/ equivocal
Thy 4 - atypia suspicious of malignancy
Thy 5 - malignant
USS FNA used to provide a minimally invasive assessment of the likelihood of malignancy

23

What can cause primary hyperparathyriodism?

Adenoma involving a single gland or hyperplasia involving all glands

24

What causes secondary hyperparathyroidism?

Chronic hypocalcaemia causes compensatory over activity of parathyroid glands

25

What causes tertiary hyperparathyroidism?

Parathyroid activity becomes autonomous associated with hypercalcaemia

26

What causes hypoparathyroidism?

Usually post-operatively (removal by accident)
Rarely congenital absence - DiGeorge syndrome
Familial - associated with primary adrenal insufficiency and mucocutaneous candidiasis (AI basis)

27

What is the most common cause of hyper/hpothyroidism?

Autoimmune thyroid disease

28

What blood results would you expect to see from primary hyperthyroidism?

TSH low
T4/T3 high

29

What blood results would you expect to see from primary hypothyroidism?

TSH high
T4/T3 low

30

What blood results would you expect to see from secondary thyroid disease - pituitary gland failure?

TSH low
T4/T3 low

31

What blood results would you expect to see from secondary thyroid disease - TSHoma?

TSH high
T4/T3 high

32

What blood results would you expect to see from primary subclinical hypothyroidism?

TSH high
T3/T4 normal
Probably end up as overt hypothyroidism

33

Define hypothyroidism.

Results from a variety of abnormalities that cause insufficiet secretion of thryoid hormones

34

What causes primary hypothyroidism?

Iodine deficiency #1
AI - Hashimoto's thyroiditis #1
Hereditary biosynthetic defects
Maternally transmitted antithyroid agents, iodides
Drug induced - amiodarone, lithium, thalidomide

35

What can cause secondary hypothyroidism?

Hypothalamic - congenital, infiltration, infection, malignancy
Pituitary - Panhypopituitarism, isolated TSh deficiency

36

What are the symptoms of hypothyroidism?

tiredness/ malaise
Weight gain
Cold intolerance
Goitre
Contipation
Menorrhagia - later oligo or ammenorrhoea
Arthralgia
Myalgia
Physchosis
Poor libido

37

What are the signs of hypothyroidism?

Dry skin and dry thin hair
Periorbital puffiness
Pitting oedema
Mental slowness
Slow relaxing reflexes
Carpal tunnel syndrome
Hyperprolactinaemia
bradycardia
worsening of heart failure

38

What Ix should be used for hypothyroidism and what would their positive result be?

TSH high
T4/T3 low
Elevated CK
Increases LDL cholesterol
Hyponatraemia
Hyperprolactinaemia
Macrocytosis is typical – rule out a concurrent Vit B12 deficiency

39

What is Hashimoto's Thyroiditis?

Gradual autoimmune destruction through antibody dependent cell mediated cytotoxicity, of the thyroid gland resulting in decreased thyroid hormone production

40

What autoantibodies are present in Hashimoto's thyroiditis?

Anti-TPO (95%)
Anti-thyroglobulin antibody (60%)
TSH receptor antibody (10-20% - blocking)

41

How is hypothyrodism managed?

Restore normal metabolic rate gradually
younger pts - thyroxine at 50-100mcg daily
elderly with history of IHD - thyroxine at 25-50mcg daily - adjusted every 4 weeks according to response

42

In pregnancy the dose requirements of thyroxine increaaase by how much?

25-50% (increased TBG)

43

Who is usually affected by a myxoedema coma?

Elderly women with longstanding but frequently unrecognised/ untreated hypothyrodisim

44

How does a myxoedema coma present?

bradycrdia
type 2 respiratory failure

45

If a patient is on amiodarone, what should they have checked frequently?

TFTs

46

List some causes of Hyperthyroidism

Graves disease
Multi-nodular goite
Toxic nodule (adenoma)
Subacute thyroiditis/De Quervains
Post-partum thyroiditis
Rare - iodine and medications (amiodarone, lithium, kelp)

47

List the symptoms of hyperthyroidism.

Tremor
Palpitations
Sweating
Irritability Diarrhoea
Weight loss
Lighter/less frequent periods
increased appetite
intolerance to heat

48

What are the clinical signs of hyperthyriodism?

Tachycardia or AF
Proximal muscle wasting
goitre with bruit
warm peripheries
lid lag
palmar erythema
onycholysis

49

What are the treatment options for hyperthyriodism?

Carbimazole
Propylthiouracil
Fluid restriction
Radioiodine and surgery may also be considered
Symptom Tx = beta-blocker (Propanolol)

50

What positive investigations indicate Graves disease?

High T3/T4, low TSh
Anti-TPO +ve (70-80%
Anti-thyroglobulin +ve (30-50%)
TSH receptor antibody +ve (70-100% - stimulating)

51

What additional S&S are present in Grave's disease?

Exophalmus
Chemosis
visual loss
proptosis
diplopia
pretibial myxoedema

52

What may trigger De Quervains?

Viral infection - other symptoms ay be present - sore throat, fever, etc)

53

What blood results are seen in De Quervains?

T4 - high in early stage, low in late stage then normal
TSH - low in early stage, high in late stage then normal

54

What treatment is required for a thyroid storm?

ABCDE
May require ventilation
Lugol's iodine
Glucocorticoids
PTU
beta-blocker
fluids
monitoring

55

How does a thyroid storm present?

Respiratory and cardiac collapse
Hypertermia
Exaggerated reflexes

56

What precautions should be followed if you are on radio-active iodine?

avoid close prolonged contact with children and pregnancy women
Avoid sharing a bed for x days
avoid pregnancy for 6-12 months
ensure not pregnant at start
high risk of hypothyroidism (esp. in Graves)