Thyroid Pathology

Question 1

What are the mechanical and functional consequences of thyroid disease?

Answer 1

Mechanical:

• Goitre
• Compression effects (airway, oesophagus, large vessels)

Functional:

• Hyperthyroidism
• Hypothyroidism
• EUthyroidism

Question 2

What is the most common cause of hypothyroidism in infacy/early childhood?

What cna it cause?

Answer 2

Usually caused yb dietary iodine deficiency.

Causes impaired development of skeleton and CNS (short statue, mental impairment)

Question 3

What are the major causes of hypothyroidism for adults?

Answer 3

Primary problem with the thyroid:

• Inflammatory thyroiditis
• Autoimmune thyroiditis (Hashimoto’s)
• Primary iodine deficiency

Question 4

In which demographics does hypothyroidism most frequently occur

Answer 4

• >60y.o.
• Women (Autoimmune thyroiditis is far more common in women)

Question 5

What is the consequence of chronic hypothyroidism?

Answer 5

Myxedema - slowing of mental and physical activity

• Fatigue
• Cold intolerance
• Overweight
• Decreased cardiac output
• Decreased sympathetic activity

Question 6

What is Hashimoto’s thyroiditis?

What are the pathological findings?

Answer 6

Autoimmune disease - loss of self-tolerance to thyroid antigens

• Female predominance

Patholigical findings:

• Apoptosis of epithelial cells
• Atrophy
• Fibrosis

Question 7

What is thyrotoxicosis?

Answer 7

Hyperthyroidism

Question 8

What are the symptoms of thyrotoxicosis for younger and older patients?

Answer 8

Young patients tend to exnhibit symptoms of sympathetic activation, older patients have more cardiovascular symptoms:

• Nervousness, anxiety, hyperactivity
• Heat intolerance
• Palpitations
• Tachycardia, hypertension
• Muscle weakness
• Weight loss despite increased appetite

Question 9

What are the three most common causes of hyperthyroidism?

Answer 9

• Diffuse hyperplasia (Graves disease)
• Hyperfunctional multionodular goitre
• Hyperfunctiona thyroid adenoma

Question 10

Are most carcinomas functional or non-functional?

Answer 10

Most are non-functional.

Question 11

What is Grave’s disease?

Answer 11

Autoantibodies against TSH receptor and other thyroid antibodies.

Thyroid can become very large, with functional symptoms.

Question 12

What are the symptoms characteristic of Grave’s disease?

Answer 12

• Pretibial myxedema
• Opthalmopathy (periorbital oedema, lid lag)

Question 13

What is nodular colloid goitre and what does it cause?

Answer 13

Iodine deficiency = reduced hormone production.

Thyroid follicles are stimulated to work harder, inducing hyperplasia.

Cycles of hyperplasia lead to nodule formation - multinodular colloid goitre.

Question 14

How do most nodular colloid goitres present in terms of thyroid hormone production?

Answer 14

Euthyroid

• However, it is the most common cause of thyroidectomy in Australia as it can cause hyperthyroidism

Question 15

Describe the pathological presentation of most thyroid neoplasms

Answer 15

• Most present as solitary nodules
• Most are non-functional

Question 16

What are the two types of thyroid adenomas?

Which is more common?

Answer 16

1. Follciular adenoma (most)
2. Hurthle cell adenoma

Question 17

What are the path features of thyroid adenomas?

Answer 17

• Solitary nodules
• Well circumscribed and encapsulated
• Normal background thyroid
• No invasion
• Majority are non-functional

Question 18

What is the treatment for thyroid adenomas?

Answer 18

Hemithyroidectomy.

Question 19

What are the 4 types of thyroid carcinomas and their prevalence?

Answer 19

1. Papillary (80%)
2. Follicular (15%)
3. Anaplastic (2%)
4. Medullary neuroendocrine (3%)

Question 20

How does follicular carcinoma typically look like?

Answer 20

Similar to follicular adenoma:

• Solitary nodule
• Thickly encapsulated

However:

• Capsular invasion
• Lymphovascular invasion
• Extrathyroidal extension

Question 21

Is papillary carcinoma usually multifocal or solitary nodule?

Answer 21

Multifocal

Question 22

Prognosis of papillary and follicular carcinoma?

Treatment?

Answer 22

Good.

Treatment = complete thyroidectomy

Question 23

Which is the most aggressive form of thyroid cancer with a very poor prognosis?

Answer 23

Anaplastic thyroid carcinoma

• Aggressive
• Often preceded by follicular or papillary carcinoma
• Multifocal