Thyroid

Question 1

Goitre pathogenesis

Answer 1

Impaired T3/T4 synthesis leads to lowered
circulating T3/T4, which increases TSH production
• Increased TSH levels act on the thyroid gland -> hypertrophy & hyperplasia of follicular cells

Question 2

Graves disease pathogenesis

Answer 2

Breakdown in self-tolerance to thyroid auto-antigens,
resulting in the production of multiple autoantibodies:
– Thyroid-stimulating immunoglobulin (TSI): Binds to TSH receptor & mimics TSH -> T3/T4 production
– Thyroid growth-stimulating immunoglobulin (TGI): Binds to TSH receptor -> induces proliferation of follicular cells
– TSH-binding inhibitor immunoglobulin (TBH): Binds to TSH receptor to block normal TSH binding

Question 3

Graves Histo

Answer 3

pseudopapillae
pale scalloped colloid
lymphocytic infiltration

Question 4

papillary thyroid carcinoma histo

Answer 4

orphan annie eye nuclei
nuclear grooves
intranuclear inclusions
psammoma bodies

Question 5

spread of PTC

Answer 5

lymphatic spread

Question 6

spread of follicular thyroid carcinoma

Answer 6

hematogenous spread (FB)