Hyperplasia

Question 1

Thyroid hyperplasia

Answer 1

• non-neoplastic proliferative growth of the thyroid gland
  1. Simple goitre
  2. Multinodular goitre

Question 2

Pathogenesis of thyroid hyperplasia

Answer 2

• Impaired synthesis of thyroid hormones eg iodine def
• lowered circulating thyroid hormone levels
• compensatory increase in TSH prod by ant pit
• increased TSH - hypertrophy & hyperplasia of follicular cells
• compensatory enlargement of thyroid gland (to overcome hormone def - simple goitres usually euthyroid)
• recurrent hyperplasia & involution - uneven nodular enlargement - mng

Question 3

Causes of simple goitre

Answer 3

1. Endemic
   - low iodine levels eg Alps, Himalayas
   - goitrogens eg cauliflower
2. Sporadic
   - congenital enzymatic defects

Question 4

Morphology of simple goitre

Answer 4

1. Hyperplastic stage
   - diffuse ild enlargement
   - crowded columnar cells forming pseudopapillae
2. Colloid involution
   - flattened cuboidal epithelium
   - abundant colloid (brown glassy cut surface)

Question 5

Clinical features of simple goitre

Answer 5

• diffuse enlargement

- euthyroid but slightly increased TSH

Question 6

Features of MNG

Answer 6

• progression from simple goitre

- extreme, irregular, asymmetrical

Question 7

Clinical features of MNG

Answer 7

1. Asymmetrical nodular enlargement, often with dominant palpable nodule
2. Mass effects - airway obstruction (trachea), dysphagia, hoarseness (rec laryngeal nearve), SVC syndrome
3. Cosmetic issues, may mimic neoplasms
4. Usually euthyroid

Question 8

Morphology of MNG

Answer 8

G:

• multilobulated asymmetrical enlargement
• cut section is brown, gelatinous colloid
• hemorrhage
• cystic change

M:

• colloid-rich follicles lined by crowded columnar cells - pseudopapillae appearance
• lacks fibrous capsule - distinguishes from follicular adenomas