11 - Thyroid Path

Question 1

which thyroid hormone is the most bioavailable?

Answer 1

T3 - T4 is almost entirely bound to TBG

Question 2

MC cause hypothyroidism in iodine-sufficient regions

Answer 2

Hashimoto’s thyroiditis

Question 3

iodine def in children called

Answer 3

cretinism

Question 4

myxedema - what is it, what conditions is assoc w/

Answer 4

accumulation of mucopolysaccharides in connective tissue

assoc w/ Hashimoto’s or surgical/radioablation of thyroid

Question 5

path of hashimoto thyroiditis

Answer 5

intense lymphocytic infiltration w/ formation of follicles w/ germinal centers

Question 6

path of subacute (DeQuervain’s) thyroiditis

Answer 6

early - destruction of follicular epithelium w/ microabscesses
lymphocytes/histiocytes/giant cells
late - chronic inflammation w/ focal fibrosis

Question 7

what causes the early transient hyperthyroid phase in thyroiditis?

Answer 7

disruption of follicular epithelium leads to release of extra thyroid hormone

Question 8

Reidel thyroiditis

Answer 8

rare form

mainly involves extensive adhesive fibrosis to adjacent structures in neck

Question 9

path of Graves dz

Answer 9

both hypertrophy and hyperplasia of follicular epithelial cells
diminished pale colloid

Question 10

path of multinodular goiter

Answer 10

colloid lakes, alternating with hyperplastic follicles, hemorrhage and hemosiderin deposition, fibrosis, cysts, and calcification

Question 11

MC thyroid congenital abnlmality

Answer 11

thyroglossal duct cyst

Question 12

which cells in parathyroid make PTH?

Answer 12

chief cells

Question 13

how do you differentiate a parathyroid adenoma from simple hyperplasia?

Answer 13

adenoma will have a rim or nl parathyroid w/ adipose tissue, while hyperplasia will have solid areas almost devoid of stromal fat