Workup/Staging

Question 1

What % of palpable thyroid nodules are malignant?

Answer 1

Only 5% of palpable thyroid nodules are malignant.

Question 2

In a pt with low TSH and a nodule that shows uptake on I-123 or Tc-99 scan, what is the likely Dx?

Answer 2

Adenomas commonly present with low TSH and increased uptake on I-123 or Tc-99 scans.

Question 3

Which TCa subtypes are difficult to distinguish from adenomas on FNA?

Answer 3

Follicular and Hürthle subtypes are difficult to distinguish from adenomas. Histologically, they show only follicular structures. Papillary TCa shows both papillary and follicular structures, which helps to distinguish it from adenomas.

Question 4

What pathologic criteria must be met to make the Dx of Hürthle cell TCa?

Answer 4

The Dx requires hypercellularity with >75% Hürthle cells (also referred to as oncocytic cells), which are characterized by abundant eosinophilic granular content.

Question 5

Which TCa subtype is more likely to present with N+ Dz: papillary or follicular?

Answer 5

Papillary TCa (∼30% node+) is more likely to spread to LNs than follicular (∼10% node+).

Question 6

Name the 2 major and 3 minor prognostic factors for DTCa.

Answer 6

Major: age and tumor size (<55 yo, ≤4 cm, respectively, have better prognosis)

Minor: histology, local tumor extension, LN status

Question 7

What variables constitute the mnemonic AMES risk group system?

Answer 7

Age, Metastasis, Extent, Size

Question 8

Which pts are low risk?

Answer 8

Young (<55 yo), no DMs

Older with minor tumor capsule involvement and tumor <4 cm and no DMs

Question 9

For TCa, what sizes distinguish AJCC 8th edition T1, T2, and T3 tumors?

Answer 9

T1: ≤2 cm (T1a if ≤1 cm; T1b if >1 cm)

T2: 2–4 cm (limited to thyroid)

T3: >4 cm (T3a if in thyroid; T3b if any size and extension into strap muscles only)

Question 10

What is the difference b/t T4a and T4b TCa lesions?

Answer 10

T4a: gross extension but still technically resectable (invasion of larynx, trachea, esophagus, SQ tissues, recurrent laryngeal nerve)

T4b: unresectable Dz (invasion of prevertebral fascia/spine, carotid artery encasement, mediastinal vessels)

Question 11

What is the difference b/t N1a and N1b in TCa?

Answer 11

N1a: mets to any level VI (pre-/paratracheal, prelaryngeal) or VII (cervical neck, upper mediastinal) LNs; unilat or bilat

N1b: mets to levels I–V, or retropharyngeal LNs

Question 12

List the latest AJCC 8th edition (2018) stage groupings for papillary and follicular TCa.

Answer 12

Stage I: M0 and age <55 yrs or T1–2N0M0 and age ≥55 yrs

Stage II: M1 and age < 55 yrs or T1–2N1, T3N(any) and age ≥55 yrs

Stage III: T4aN(any)M0 and age ≥55 yrs

Stage IVA: T4bN(any)M0 and age ≥55 yrs

Stage IVB: T(any)N(any)M1 and age ≥55 yrs

Question 13

What is unique about the staging of nonmedullary TCa?

Answer 13

It is age dependent; it differs for pts > or <55 yo.

Question 14

Can a pt <55 yo with follicular or papillary TCa have stage III or IV Dz?

Answer 14

No. A pt <55 yo with follicular or papillary TCa cannot have stage III or IV Dz.

Question 15

What is the stage of a 37-yo pt with Hurthle TCa and a solitary bone met?

Answer 15

Stage II. If the pt were 56 yo, he or she would be stage IVB.

Question 16

What is the stage of a 56-yo pt with an unresectable primary DTCa and no mets?

Answer 16

Stage IVA. If pt was 44 yo, he or she would be stage I.

Question 17

What must be done prior to an I-123 or I-131 scan?

Answer 17

TSH stimulation must be done prior to an iodine scan.

Question 18

What are 2 ways to do TSH stimulation?

Answer 18

TSH stimulation can be accomplished through thyroid hormone withdrawal or by using recombinant TSH.

Question 19

What are some advantages of recombinant TSH stimulation?

Answer 19

Fewer side effects and a shorter period of elevated TSH (theoretically, a lower risk of tumor progression)

Question 20

What are the approved indications for recombinant TSH stimulation?

Answer 20

Recombinant TSH is approved for f/u iodide scans and for the I-131 Tx of low-risk pts.

Question 21

What sites of the body show a physiologic uptake of iodide?

Answer 21

The salivary glands and the GI tract show physiologic uptake d/t the presence of iodide transporters.

Question 22

What is the 10-yr OS for papillary vs. follicular TCa?

Answer 22

Similar when matched for stage, 85%–95%

Question 23

Is the presentation and Tx of Hürthle cell carcinoma more similar to that of papillary or follicular TCa?

Answer 23

It is more similar to follicular TCa; however, Hürthle cell carcinoma has a slightly higher DM rate and worse prognosis (10-yr OS ∼70%–80%).

Question 24

Estimate the 10-yr OS for pts with localized vs. N+ medullary TCa.

Answer 24

For localized medullary TCa, the 10-yr OS is ∼90%. If N+, the 10-yr OS is ∼70%.

Question 25

What are the stage groupings for anaplastic TCa?

Answer 25

All anaplastic TCa is stage IV. Stage IVA is T1–3aN0 (resectable), stage IVB is N1 or T3b–4 (unresectable), and stage IVC is metastatic.

Question 26

Estimate the MS and the 1-yr OS for pts with anaplastic TCa.

Answer 26

MS is ∼6 mos and the 1-yr OS is ∼20% for all pts with anaplastic TCa.

Question 27

Does the tall cell variant have a more favorable or unfavorable prognosis when compared to classic papillary TCa?

Answer 27

The tall cell variant has an unfavorable prognosis (10-yr OS ∼75%) when compared to classic papillary carcinomas.

Question 28

What is the most frequent site of DM in papillary and follicular TCa?

Answer 28

Lung (∼50%), f/b bone, CNS