Pathology

Question 0

What is the normal histology of thyroid follicles?

Answer 0

• lined by epithelial cells
• various sizes
• filled with colloid (thyroglobulin) stains pink in H&E
• thin fibrous septa with rich blood supply
• C cells in interstitium

Question 1

What is the effect of high TSH on thyroid follicle?

Answer 1

Thyroid follicle becomes larger

Produces more colloid

Question 2

What are the histological features of an inactive follicle?

Answer 2

low cuboidal cells

follicle filled with colloid

Question 3

What are the histological features of an active thyroid follicle?

Answer 3

tall cuboidal to columnar cells

scalloping of colloid

Question 4

What is thyrotoxicosis?

Answer 4

Includes hyperthyroidism
Elevated T3 and T4 leading to hypermetabolic state and SNS overactivity
usually, TSH is low and T4 is high

Question 5

What are common causes of hypothyroidism?

Answer 5

• Hashimoto’s thyroiditis (autoimmune)

- iodine deficiency

Question 6

What are common causes of thyrotoxicosis?

Answer 6

• Grave’s disease (diffuse hyperplasia)

- Hyperfunctioning multinodular goiter

Question 7

What is diffuse non-toxic goitre?

Answer 7

• low thyroid hormone causing elevation of TSH as compensatory response
• usually euthyroid
• goitre will involute if TSH and thyroid hormones return to normal

Question 8

What are the histological features of diffuse non-toxic goitre?

Answer 8

• hyperplastic follicles
• follicles lined by crowded cells
• some follicles larger than others
• follicles involute if high TSH resolves (low cuboidal epithelium and abundant colloid)
• follicles rupture/haemorrhage/fibrose or grow larger if persistently high TSH

Question 9

What is the histopathology associated with Hashimoto’s thyroiditis?

Answer 9

• Mononuclear inflammatory infiltrate
• antibodies against thyroglobulin and thyroid peroxidase
• germinal centres
• follicles appear eosinophilic with granular cytoplasm
• fibrosis and scarring causes thickening of interstitial CT

Question 10

What is the histopathology associated with Graves’ disease?

Answer 10

• tall follicular cells
• crowded cells
• may form papillae
• diffuse hypertrophy
• diffuse hyperplasia
• widespread scalloping
• colloid is often paler
• lymphocytic infiltrate

Question 11

What is the gross pathology of Hashimoto’s thyroiditis?

Answer 11

enlarged thyroid at first then eventually atrophies
fibrotic (pale)
nodular
firm

Question 12

What is the gross pathology of Graves’ disease?

Answer 12

diffuse symmetrical enlargement of thyroid