Pathology of the Thyroid and Parathyroid Glands

Question 1

What things can cause goitre?

Answer 1

• euthyroid: normal function (diffuse in younger/multinodular in older)
• hypothyroidism: iodine deficiency, goitrogens (drugs eg. lithium/amiodaron, diet eg. cabbage and turnips) - interfere with normal thyroid function

Question 2

What are the pathogeneses of goitres?

Answer 2

• reactive
• iodine block
• genetic

Question 3

Contrast the signs of a benign vs possibly malignant mass in the neck

Answer 3

Benign:

• soft
• moveable
• non-tender

Malignant:

• hard
• fixed to surrounding tissue
• tender with regional lymphadenopathy

Question 4

If someone presents with a neck mass and hoarseness and dysphagia, what are we worried about?

Answer 4

possible damage to the recurrent laryngeal nerve (supplies intrinsic muscles of larynx and sensation below level of vocal cords)

Question 5

List some diagnostic tests you would want to do if suspicion of thyroid disease

Answer 5

• thyroid function tests: measure TSH (high - thyroiditis, low - aautonomous/hypoerfunctioning nodule)
• antithyroid antibodies: good test for Hashimoto’s disease
• FBC: good for testing for abscesses
• fine needle aspiration for cytology

Question 6

List some imaging studies you can do for neck masses

Answer 6

• ultrasonography (determine if cystic/solid/mixed)
• radioiodine scintigraphy (determine if cold/warm/hot)
• chest radiography (if malignancy suspected to check for metastases)
• CT
• MRI

Question 7

What are the immune and genetic associations with Graves disease?

Answer 7

Immune: IgG against TSH on thyrocytes

Genetic: HLA-DR3 and CTLA-4

Question 8

What are the immune and genetic associations with Hashimoto’s disease?

Answer 8

Immune:

• autoreactive CD8 T lymphocytes
• autoreactive antibodies
• blocking TSH antibodies

Genetic: family history of Hashimoto’s or other autoimmune diseases

Question 9

List the types of thyroid tumours

Answer 9

Benign: follicular adenoma

Malignant:
- papillary (from thyroid epithelium and forming papillae)
- follicular 
- anaplastic (undifferentiated)
- medullary (from C cells)
^ form carcinomas
- lymphoma (common in Hashimoto's)
- metastatic lymphoma

Question 10

What are the causes of papillary carcinomas?

Answer 10

• radiation
• family history
• unknown

Question 11

Contrast the feeling of a papillary carcinoma vs follicular carcinoma in clinical practice

Answer 11

Papillary carcinoma spreads to local lymph nodes - so patient presents with local lymphadenopathy

Follicular carcinoma does not spread to lymph nodes - so patient presents with hard nodule but no lymph node enlargement
- can spread to bone through the blood

Question 12

Describe the clinical signs of hypercalcaemia

Answer 12

• muscle atrophy
• emotional disorders
• parathyroid adenoma/hyperplasia
• peptic ulcer
• pancreatitis
• kidney stones
• nephrocalcinosis

Question 13

What are the causes of hyperparathyroidism?

Answer 13

Primary: adenoma (most), hyperplasia, carcinoma
Secondary: low calcium (eg. chronic renal failure/vit D deficiency)
Tertiary: raised calcium in secondary