157 Thyroid histo/path

Question 1

Thyroid

-embryological origin?

Answer 1

1st pharyngeal arch

endodermal origin

Question 2

what connects thyroid to the base of the tongue?

Answer 2

thryoglossal duct - should obliterate during gestation –> if not, pathology as adult

Question 3

do thyroid nodules move with deglutition?

Answer 3

yes

Question 4

Thyroid - histo

Answer 4

capsule penetrates and divides into lobules

20-40 follicles per lobules

Question 5

what surrounds colloid?

Answer 5

simple follicular epithleium

Question 6

what do C-cells secrete? what cancer do they cause?

Answer 6

calcitonin

medullary carcinoma

Question 7

how are thyroid nodules evaluated?

Answer 7

FNA

Question 8

what causes a midline mass superior to the isthmus? histo? treatment?

Answer 8

thyroglossal duct cyst - failure of atrophy

cyst w/ squamous epi filled with proteinaceous fluid

surgery requires removal of hyoid bone (cosmetic surgery)

Question 9

Chronic lymphocytic (Hashimoto) thyroiditis
-cause?

Answer 9

autoimmune abs –> TG and TPO

Question 10

Chronic lymphocytic (Hashimoto) thyroiditis
-macro appearance?

Answer 10

diffusely enlarged gland

Question 11

Chronic lymphocytic (Hashimoto) thyroiditis
-micro appearance?

Answer 11

inflammatory cells with germinal cells
follicles atrophy with Hurthle cells (follicular epi cell regenerate with metaplasia) –> big pink cells with lots of mitochondria

Question 12

Chronic lymphocytic (Hashimoto) thyroiditis
-risk?

Answer 12

other autoimmune disease

b-cell non-hodgkin lymphomas

Question 13

Graves’ Disease - cause

Answer 13

autoimmune Abs against TSH receptor –> activating (hyperthyroidism)

Question 14

Graves’ Disease - presentation

Answer 14

hyperplasia of gland - diffuse enlargement
ophthalmopathy - eyes are large
dermatopathy - skin changes

Question 15

Graves’ Disease - treamtent

Answer 15

1st - radioactive

if fail - surgery

Question 16

Graves disease - micro histo

Answer 16

papillary hyperplasia with tall follicular cells

lack nuclear features of papillary carcinoma

Question 17

Adenomatous/Colloid/ Hyperplastic Nodule

Answer 17

benign hyperplastic nodule/goiter

Question 18

Adenomatous/Colloid/ Hyperplastic Nodule - single or multiple

Answer 18

usually multiple

Question 19

Adenomatous/Colloid/ Hyperplastic Nodule - histo

Answer 19

hyperplastic –> outgrow vasculature –> necrosis and hemorrhage –> dystrophic calcification –> involution

repeat cycles of hyperplasia and involtion –> nodules

Question 20

Thyroid Neoplasms

Answer 20

adenomas = benign
carcinoma = malignant

Question 21

Follicular/Hurthle Cell Adenoma - mutiple or single nodules?

Answer 21

usually single from follicular epithelium

can’t distinguish from follicular carcinomas until excised

Question 22

Follicular/Hurthle Cell Adenoma

Answer 22

intact capsule surrounding small follicles (rosettes) - carcinomas break through capsule and vasculature
(other nodules don’t have a capsule)

monoclonial (nodules are often polyclonial)

Question 23

Follicular/Hurthle Cell Carcinoma

Answer 23

capsular invasion
vascular invasion

RAS and PAX8 mutations are common

Question 24

most common thyroid carcinoma? cause? mutations? spread?

Answer 24

papillary carcinoma

radiation

MAP kinase pathway
RET
BRAF activating point mutation

lymph - can be mulitfocal so must take out entire gland with surgey

Question 25

Papillary carcinoma - histo

Answer 25

orphan annie eyes
atypical nuclear morphology
nuclear grooves
intranuclear inclusion
psammaoma body - Ca circles at papilla

Question 26

MTC - cell type? mutation?

Answer 26

C-cells

can occur with MEN 2A/2B

RET

Question 27

MTC appearance

Answer 27

non-encapsulated

middle to upper thyroid lobes

Question 28

what tyroid cancer has the worst prognosis?

Answer 28

anaplasitic (undifferentiated) carcinoma

Question 29

Thyroid Lymphoma

Answer 29

usually NHL, B cell type

usually in setting of Hashimoto’s