Thyroid and Parathyroid Pathology

Question 1

What is a ‘goitre’?

Answer 1

Swollen, enlarged thyroid gland

Question 2

What is euthyroid?

Answer 2

Normal thyroid gland function

Question 3

What people get a diffuse goitre thyroid?

Answer 3

Yonger people

Question 4

What people get a multinodular goitre thyroid?

Answer 4

Older people

Question 5

What can cause hypothyroidism?

Answer 5

Iodine deficiency - endemic (seaweed may cause hyperthyroidism)

Goitrogens

• Drugs - Lithium, amiodarone
• Diet - cabbage, turnips

Question 6

What is the most common drug that can cause goitre?

Answer 6

Lithium

Question 7

What can the pathogenesis of hypothyroidism be?

Answer 7

• Reactive
• Iodine block
• Genetic

Question 8

How do benign masses and malignancies differ in the thyroid on inspection?

Answer 8

• Benign masses are usually movable, soft and non-tender

- Malignancy is associated with a hard nodule, fixation to surrounding tissue, and regional lymphadenopathy

Question 9

What are the signs and symptoms of hyperthyroidism?

Answer 9

• Nervousness
• Heat intolerance
• Diarrohea
• MUscle weakness
• Loss of weight and apetite

Question 10

What are the signs and symptoms of hypothyroidism?

Answer 10

• Cold intolerancce
• Constipation
• Fatigue
• Weight gain

Question 11

What are signs / symptoms of local nerve involvement in a thyroid pathology?

Answer 11

• Dysphagia and hoarsness

- Could be a sign of malignancy

Question 12

What do the follicles look like on histology in multinodular goitre?

Answer 12

Different sizes

Question 13

How is a thyroid pathology diagnosed?

Answer 13

• Thyroid function test
• Antithyroid antibodies
• Complete blood count
• Fine needle aspirate
  Imaging
• Ultrasnogtophy
• Radioiodine scintigraphy
• Chest radiography
• CT, MRI

Question 14

What may an elevated thyroid-stimulating hormone (TSH) indicate?

Answer 14

Thyroiditis

Question 15

What may a very low TSH level indicate?

Answer 15

An autonomous or hyperfunctioning nodule

Question 16

What are antithyroid antibodies helpful in?

Answer 16

Diagnosing chronic lymphocytic thyroiditis (Hashimoto thyroiditis)

Question 17

What can a solitary thyroid nodule be?

Answer 17

• Abcess

- Thyroid pathology

Question 18

What are the diseases of the thyroid?

Answer 18

• Trauma
• Toxicity (lithium)
• Goitre, solitary nodule, neoplasms
• Chronic inflammation - immune or not
• Acute thyroiditis, abscess
• Metabolic, genetic

Question 19

What is the classic sign of an overactive thyroid?

Answer 19

Exophthalmos (buldging of the eye) (build up of fatty tissue pushing eyeball forward)

Question 20

What is the most common cause hyperthyroidism?

Answer 20

• Graves (may present as diffuse toxic goitre)

Question 21

What can cause hyperthyroidism?

Answer 21

• Graves
• Functional goitre
• Toxic adenoma

Question 22

What can cause hypothyroidism?

Answer 22

• Congenital

- Autoimmune (commonest in adults)

Question 23

What happens in hypothyroidism?

Answer 23

• Defective TH production
• Loss of parenchyma
• Deficient TSH

Question 24

What is graves disease caused by?

Answer 24

• IgG against TSH receptor on thyrocytes
• Antibody is not compliment fixing IgG class 2 or 4 not 1 or 3
• Mimics TSH

Question 25

What gender is more likely to get Graves disease?

Answer 25

female - 10:1 over males

Question 26

What may Graves disease present as?

Answer 26

Diffuse toxic goitre

Question 27

What genes may cause graves?

Answer 27

Strong family history HLA DR3 and CTLA-4

Question 28

What group of people are most likely to be affected by Hashimoto thyroiditis?

Answer 28

Female 30-50 (again ~ 10:1 ratio against males)

Question 29

Describe the pathogenesis of Hashimoto thyroiditis?

Answer 29

- Autoreactive CD8 T lymphocytes - Autoreactive antibodies: thyroid microsomal in almost all 95% thyroglobulin in 2/3s, minority have blocking TSH receptor antibodies - Can cause hyper or hypothyroidism (primarily hypothyroidism)

Question 30

What may the thyroid gland look and feel like in hashimoto thyroiditis?

Answer 30

- Multinodular - Shrunken - Hard - Fibrotic - Scarring

Question 31

What can cause hashimoto thyroiditis?

Answer 31

- FH (like many autoimmune diseases) - Increased iodine intake - Viral infection

Question 32

What is a long term risk of hashimoto thyroiditis?

Answer 32

Lymphoma

Question 33

What are benign neoplasms of the thyroid?

Answer 33

Follicular adenoma

Question 34

What are malignant neoplasms of the thyroid?

Answer 34

- Primary about 1% of cancers; papillary, follicular, anaplastic, medullary (parafollicular cells), lymphoma - Metastic: Lymphoma

Question 35

Who is likely to be affected by follicular adenomas?

Answer 35

Females: 30 - 50 years

Question 36

How large are the follicular adenomas usually?

Answer 36

1 - 3 cm at presentation (small, incapsulated, not usually invasive)

Question 37

What is the most common cause of thyroidd cancer?

Answer 37

Papillary carcinoma (80%)

Question 38

What group does papillary carcinoma affect?

Answer 38

Females (3:1) 20 - 50 years

Question 39

What are the causes of papillary carcinomas?

Answer 39

- Radiation (Chernobyl) - Family History - Unknown

Question 40

What genes can cause papillary carcinoma?

Answer 40

- Rearrangement of RET oncogene in most | - B-RAF mutation in half - associated with increased risk of LN mets

Question 41

What does papillary carcinoma look like upon histology?

Answer 41

Instead of having pattern of regular follicles follicle linings become complex and branched forming papillary - Gobs of calcium also present

Question 42

What percentage of thyroid cancers are follicular carcinomas?

Answer 42

20%

Question 43

What group does follicular carcinomas affect?

Answer 43

- Females:Males (3:1) | - Older than 40

Question 44

What genes can cause follicular carcinoma?

Answer 44

- RAS oncogene | - PAX8/PPARG rearrangement

Question 45

How can folllicular carcinoma spread?

Answer 45

- Minimally invasive versus invasive | - Blood spread may present in bone marrow

Question 46

What is anaplastic carcinom?

Answer 46

- Less common - p53 mutation common - May have had previous thyroid neoplasia - Half have had chronic goitre - Female:Male 4:1

Question 47

What cells are attacked in medullary carcinoma?

Answer 47

Parafollicular cells (tumors can produce amyloid instead of calcitonin)

Question 48

What genes can be involved in medullary carcinoma?

Answer 48

RET proto-oncogene activation (20% familial, in youngeer patients)

Question 49

What are the causes of primary hyperparathyroidism?

Answer 49

- Adenoma (4/5s) - Hyperplasia (some familial) - Parathyroid carcinoma (less than 1%)

Question 50

What are the causes of secondary hyperparathyroidism?

Answer 50

- Caused by low calcium (e.g chronic renal failure and vitamin D deficiency)

Question 51

What are the causes of tertiary hyperparathyroidism?

Answer 51

Raised caclcium in secondary

Question 52

What are the effects of hypercalcaemia?

Answer 52

- Emotional disorders - Muscle atrophy - Parathyroid adenoma or hyperplasia - Osteitis fibrosa cystica - Peptic ulcer - Pancreatitis - Kidney stone - Nephrocalcinosis - Arrhythmia - Calcification of blood vessels

Question 53

What cancer can cause hyperparathyroidism?

Answer 53

Small cell lung cancer

Question 54

What is multiple endocrine neoplasia?

Answer 54

- Genetically inherited (MEN1 and MEN2) - Associated with tumours in the endocrine organs (specifically parathyroid and neuroendocrine cell and parafollicular calcitonin producing cell in thyroid)