01-21 Thyroid Nodules and Cancer

Question 1

Epidemiology of thyroid nodules

Answer 1

super common
— >50% in persons > 50 y/o
—majority are benign
—increasingly incidentalomas

Question 2

Pemberton’s sign

Answer 2

plethora/lightheadedness when lifting hands over overhead

—goiter causing SV syndrome

Question 3

Low TSH and high T4 makes you think what about a goiter?

Answer 3

that it is fxn’ing autonomously

Question 4

Multinodular goiter
—A.K.A.
—GROSS
—HISTO

Answer 4

A.K.A.
—Simple (Non-toxic) Goiter/ Nontoxic Multinodular Goiters (MNG)

GROSS: enlarged, glistening color (coloid), nodularity bilaterally

HISTO: wicked enlarged follicles, can be hemorrhagic from hyerpvascularization → hemosidderin containing M0s

Question 5

Non-Toxic Goiter
—Etiology
—Sx
—Tx
—Prognosis

Answer 5

ETIOLOGY
—Heritable genetic defects in T4 biosynth
—excess iodine
—Extrinsic: (goitrogens, iodine excess, anti-thyroid Rx)

SX
—usu asx
—obstruction rarel
—cosemtic

TX
—non-needed usually
—maintain euthyroid

PROGNOSIS
—Low risk of becoming malignant

Question 6

Solitary/Dominant Thyroid nodule

Answer 6

Just one big nodule

—Question as to whether there is any point of distinguishing between this and MNG

Question 7

Initial work-up for a nodule

—Why?

Answer 7

TSH (malig nodules do NOT ↑ T4 or ‪↓‬ TSH

—and/or ultrasound

Question 8

Hot vs. cold nodules on thyroid scan

Answer 8

thyroid scan defines thyroid fxn (not anatomy)

COLD
—majority (90%)
—95% are benign, but 5% are malignant

HOT
—less common (~10%)
—never malignant
—can cause hyperT4

Question 9

Ultrasound findings

Answer 9

Cystic: you know it’s NOT malignant
Solid/Mixed: still probably not malignant, but can’t be sure

Higher risk if:
—solid & hypo-echoic (darker)
—margins aren't clear
—micro-calcifications noted
—↑ vasc in nodule(s)

Question 10

Solid Cold Nodule

—Top 3 DDx

Answer 10

MOST COMMONLY:
—dominant benign nodule in developing MNG
—benign thyroid adenoma

LESS COMMON:
—various carcinomas

Question 11

Path findings from FNA: microfollicules

Answer 11

micro-follicles are suspicious

—if FNA is suspicious → Bx

Question 12

Papillary carcinoma
—How to dx?
—Path Dx features?

Answer 12

—Most common thyroid malig (85%)
—Can be dx from cytology (i.e. FNA)
—if you see papillary, it’s always malignant
—usually indolent

DX FEATURES

1. papillary architecture
2. Psamomma bodies = micro-calcifications
3. Nuclei: orphan Annie eye & nuclear grooves

Question 13

Follicular adenoma vs. Carcinoma

—Dx features

Answer 13

ADENOMA
—encapsulated, solitary nodule
—no evidence of invasion
—microfollicular pattern w/ itty bitty colloids

CARCINOMA
—as above but invasive
—can’t ID this by cytology, need Bx
—Second-most common thyroid malig (10%)

Question 14

Aplastic Carcinoma

Answer 14

kills very fast
—wildy irregular cells w/ necrosis
—can dx w/ cytology
—very rare ( <1% of thyroid maligs)
—Killed Chief Justice Rehnquist

Question 15

Other rare thyroid malignancies

Answer 15

medullary
—C-line tumors
—secrete calcitonin
—MEN2a&b

lymphoma
—can dx from flow cytometry of FNA

Question 16

Treatment Options
Post-Op Med Needs
Follow-Up

Answer 16

TX OPTIONS
—thyroidectomy or I131 ablation (even though cancer cells don’t make T4, they still take up some I )

POST-OP
—Rx L-thyroxine for two reasons:
1. obvi to replace T4
2. but also to suppress TSH (causes tumor growth)

FOLLOW-Up
—Total body Iodine scan +/- neck US
—Follow thyroglobulin as tumor marker

Question 17

Appx what % of all thyroid nodules turn out to be malignant?
Approximately what percent of all thyroid nodules will turn out to be malignant?

A) 50-75%
B) 75+%
C) 10-25%
D) 10% or less
E) 25-50%

Answer 17

D) 10% or less

Question 18

Which pre-operative procedure is the MOST helpful to predict a thyroid malignancy in a patient with a thyroid nodule?

A) Thyroid ultrasound
B) I131  thyroid scan
C) FNA biopsy and cytology
D) Thyroglobulin level
E) CT scan of the neck

Answer 18

C) FNA biopsy and cytology

Question 19

Which of these thyroid cancers is often inherited?

Papillary carcinoma
Thyroid lymphoma
Anaplastic carcinoma
Medullary carcinoma
Follicular carcinoma

Answer 19

Medullary carcinoma
—RET proto-oncogene mutation seen in MEN2a&b
—screen the whole fam if you come across one of these

Question 20

A 50 year old woman presents with a thyroid twice normal size which has been growing very slowly over the last 10 years. She is not on any medications.
What would most likely be the result of a TSH measurement?

Suppressed
Elevated
Normal
Any of the above

Answer 20

Normal (Form (structure/size) does not reliably predict function.)
—could be any of the above, but normal is most likely

Question 21

A 35 year old woman presents with a recently discovered 2.5 nodule in the right lobe of her thyroid. On ultrasound the nodule contains many micro-calcifications and has an irregular border.

You feel several enlarged, firm cervical lymph nodes on the same side as the nodule. What do you think will be found when the nodule is surgically removed?

Thyroid cyst
Benign follicular adenoma
Papillary carcinoma
Multi-nodular thyroid
Follicular carcinoma

Answer 21

Papillary carcinoma

Question 22

Look at slides 44, 45 & 46

Answer 22

for more path quizing