Thyroid Pathology

Question 1

If the thyroid fails to descend from it embryological origin what is this called?

Answer 1

Linguinal thyroid

Question 2

If the thyroid undergoes excessive descent where is it most likely to be located?

Answer 2

Retrosternal within the mediastinum

Question 3

What are some non autoimmune causes of thyroiditis?

Answer 3

Palpation
Subacute lymphocytic infiltrate
Infection

Question 4

What is autoimmune hypothyroidism usually due to?

Answer 4

Hashimoto thyroditis

Question 5

What is autoimmune hyperthyroidism usually due to?

Answer 5

Graves disease

Question 6

What are some causes of hyperthyroidism?

Answer 6

Hyper-functioning Nodules or tumours

Graves disease

Question 7

Graves Disease

Answer 7

10F:1M 20-40years

Question 8

What causes the hyperthyroidism in graves disease?

Answer 8

Thyroid stimulating immunoglobulin

Acts independently of T3, T4 as well as TSH so isn’t inhibited

Question 9

Graves disease clinical signs

Answer 9

Diffuse thyroid enlargement
Eye changes - bulging eyes
Pretibial Myxoedema

Question 10

Why are specific tissues affected in graves disease?

Answer 10

As fibroblasts express TSH recpetors

Question 11

What is the definition of hypothyroidism?

Answer 11

Low T3 and T4 levels

Question 12

Hashimotos thyroditis

Answer 12

Middle age women

HLA DR3 / DR5

Question 13

What can also cause hypothyroidism?

Answer 13

Iodine deficiency

Question 14

What antibodies are associated with Hashimotos thyroiditis?

Answer 14

Antithyroglobulin

Anti Peroxidase

Question 15

What does the presence of antibodies in hypothyroidism result in?

Answer 15

Antibody dependant cell mediated cytotoxicity

Question 16

What to look for in hashimotos thyroiditis?

Answer 16

Diffusely enlarged thyroid
Prominent lymphoid infiltrate
Follicle atrophy 
Eosinophilic cytoplasm
Possible fibrosis

Question 17

What can precede hashimotos thyroiditis?

Answer 17

Transient hyperfunction - Hashitoxicosis

Question 18

What are those with hashimotos thyroiditis at an increased risk of?

Answer 18

B cell Non-Hodgkins Lymphoma

Question 19

What is a goitre?

Answer 19

Any enlargement of the thyroid gland

Question 20

What is the most common cause of goitre?

Answer 20

Lack of iodine

Question 21

Why does a reduced iodine level result in a goitre?

Answer 21

As iodine deficiency results in low T3 and T4
Causes increase in TSH
Stimulates enlargement of the gland in effort to restore T3 and T4 levels

Question 22

Endemic reasons for diffuse goitre

Answer 22

Iodine deficiency or ingestion of goitregenic substances

Question 23

Sporadic reasons for diffuse goitre

Answer 23

Inborn errors in metabolism - Dyshormonogenesis
F>M
Most cases are iatrogenic

Question 24

What does lab analysis of blood samples in goitre usually show?

Answer 24

T3/T4 normal

TSH high

Question 25

What is an adenoma of the thyroid called?

Answer 25

Follicular adenoma

Question 26

What are the four main carcinomas of the thyroid called?

Answer 26

Papiliary Follicular Medullary Anaplastic

Question 27

Which is the most common carcinoma?

Answer 27

Pappiliary 75-85%

Question 28

How do follicular adenomas clinically appear?

Answer 28

Discrete solitary nodule Often incidental finding Produce local symptoms e.g. dysphagia hoarse voice

Question 29

Under the microscope how do follicular adenomas appear?

Answer 29

Neoplastic thyroid follicles | Encapsulated by surrounding collagen cuff

Question 30

Why do adenomas usually produce no systemic symptoms?

Answer 30

As they are usually non functional | - some can secrete hormones causing thyrotoxicosis

Question 31

What carcinoma is related to iodine deficiency?

Answer 31

Follicular carcinoma

Question 32

What carcinoma is related to ionising radiation?

Answer 32

Papillary carcinoma

Question 33

Papilliary genetics

Answer 33

MAP kinase pathway activated and RAS mutation

Question 34

Follicular genetics

Answer 34

P13k/AKT pathway

Question 35

Anaplastic genetic

Answer 35

p53 and beta catenin mutation

Question 36

Medullary genetics

Answer 36

Familial link | MEN2 mutation

Question 37

Papilliary carcinoma

Answer 37

Usually a solitary nodule but can be multi nodular | - often cystic or calcified

Question 38

Papilliary carcinoma symptoms

Answer 38

Hoarseness dysphagia cough dysopnea - locally advanced

Question 39

How is a papillary carcinoma usually spread?

Answer 39

Lymphatic metastasis

Question 40

If a papillary carcinoma is haemotgenously spread where does it usually presen?

Answer 40

Lung | Indicates very late stage

Question 41

Prognosis in papillary carcinoma

Answer 41

10 year survival is 95%

Question 42

Follicular carcinoma

Answer 42

Slowly enlarging painless and non functional single nodule

Question 43

What is main form of metastasis in follicular carcinoma?

Answer 43

Haematogenous | Bones Lungs and Liver

Question 44

When is a follicular carcinoma difficult to distinguish from an adenoma?

Answer 44

When its minimally invasive and well differentiated

Question 45

Prognosis of an follicular carcinoma?

Answer 45

10 year survival is 50%

Question 46

Where is a medullary thyroid carcinoma derived from?

Answer 46

Neuroendocrine C-cells

Question 47

What are common systemic affects of medullary thyroid carcinoma?

Answer 47

Diarrhoea VIP production | Cushings syndrome ACTH production

Question 48

What to look for in medullary thyroid tumour?

Answer 48

Congo red stian - amyloidosis | C cell hyperplasia

Question 49

What mutation indicates familial link and more aggressive potential?

Answer 49

MEN2B

Question 50

Anaplastic

Answer 50

Undifferentiated and aggresive Rapid growth and invasion of local neck structures High mortality Older patients