Ch04. ENT Endo

Question 1

Thyroid arterial supply

Answer 1

ECA -> superior thyroid artery -> superior pole of the thyroid
Subclavian artery -> thyrocervical trunk -> inferior thyroid artery -> lateral lobes of the thyroid
Aortic arch or innominate artery -> thyroid ima artery -> thyroid isthmus

Question 2

Factors that favor malignancy

Answer 2

Males, <20 or >70 years, neural involvement (hoarseness), family history, cervical adenopathy, radiation exposure

Question 3

FNA indications

Answer 3

> 1 cm with high and intermediate suspicion
=1.5 cm with low suspicion
=2 cm with very low suspicion
Suspicious sonographic features: microcalcifications, irregular margins, marked hypoechogenicity

Question 4

Define Bethesda system for thyroid FNA

Answer 4

Conceived in 2009, reporting system where cytopathologic results are categorized into six categories.

Question 5

What is Bethesda I?

Answer 5

Nondiagnostic, risk of malignancy is 1-4%, Rx repeat FNA

Question 6

What is Bethesda II?

Answer 6

Benign, risk of malignancy is 0-3%, Rx observation

Question 7

What is Bethesda III?

Answer 7

Atypia or follicular lesion of undetermined significance, risk of malignancy 5-15%, consider molecular testing

Question 8

What is Bethesda IV?

Answer 8

Follicular neoplasm or suspicious for follicular neoplasm, 15-30%, consider thyroidectomy

Question 9

What is Bethesda V?

Answer 9

Suspicious for malignancy, risk of malignancy 60-75%, Rx thyroidectomy

Question 10

What is Bethesda VI?

Answer 10

Malignant. Risk of malignancy 97-99%, Rx thyroidectomy

Question 11

Molecular testing for thyroid cancer (name one mutation)

Answer 11

BRAF V600E is most prevalent mutation found in papillary carcinoma with nearly 100% specificity.
Molecular testing not recommended for Hurthle cell neoplasms

Question 12

Thyroid carcinoma AJCC T staging

Answer 12

T1: <= 2 cm tumor limited to thyroid (T1a <=1 cm tumor, T1b >1 cm but <=2 cm)
T2: >2 cm but <=4 cm tumor limited to thyroid
T3: >4 cm tumor or gross extrathyroidal extension invading only strap muscles (T3a >4 cm tumor limited to thyroid, T3b gross extrathyroidal extension invading only strap muscles of any size)
T4: includes gross extrathyroidal extension
- T4a invades subcutaneous soft tissue, larynx, trachea, esophagus, or recurrent laryngeal nerve
- T4b invades prevertebral fascia, encasing carotid or mediastinal vessels

Question 13

Subtypes of PTC

Answer 13

Several architectural and cytologic subtypes.
~50% are classical subtype (papillary architecture w fibrovascular cores and psammoma bodies) and tumor cells containing enlarged, overlapping nuclei with nuclear clearing (“Orphan Annie cells”)
Tall cell variant: older, bulky, extension beyond thyoid capsule; more aggressive course than conventional PTC. Refractory to radioactive iodine treatment conferring worse prognosis.
Columnar cell variant: rare, present with nec kmass. Resembles endometrial or colonic adenocarcinomas. Aggressive variant with widespread mets.
Follicular variant: between c-PTC and follicular thyroid carcinoma. Prognosis is similar except diffuse or multinodular follicular variant which confers worse prognosis.