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As I mentioned previously, in the adult,

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the most common masses that are palpated in the

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neck are thyroid nodules and lymph nodes.

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Let's talk briefly about thyroid nodules.

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When you're reading cases in the emergency room,

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particularly cervical spine CT scans for trauma,

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you will find quite a bit of thyroid nodules as incidental

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findings on the cervical spine CT or even

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on a neck CT for other purposes.

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So what are we to do with these incidental

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thyroid nodules which are so prevalent?

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Notice that the palpable thyroid nodule prevalence

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is about 5% in all women and about 1% in men.

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So if you're reading 20 CT scans of the cervical spine in an

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evening, you're going to find thyroid nodules in the women.

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When you look at ultrasound detected thyroid nodules,

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the numbers generally that are referred to are about 40% of all

0:58

comers to ultrasound for the evaluation of carotid stenosis.

1:06

So on your doppler ultrasound of the carotid artery,

1:09

about 40% of individuals show some nodularity in their thyroid

1:14

gland, which again is more common in women than in men.

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Only 5% to 10%, to 15% of thyroid nodules that

1:23

are aspirated are cancerous. And yet,

1:27

because thyroid cancer is such a benign cancer

1:31

with a 95% five-year survival and cure rate,

1:37

it's really an issue that we are over diagnosing thyroid

1:41

nodules and over diagnosing thyroid cancers,

1:43

which in general do not kill you.

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Now, there are some variants of thyroid cancers such as

1:49

anaplastic carcinoma as well as medullary carcinoma,

1:53

which have a worse prognosis.

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But 90% of the cancers are the papillary and follicular

1:59

variety, which are well differentiated and have,

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as I said, about a 95% cure rate at five years.

2:08

When you aspirate the thyroid nodules,

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the vast majorities of these may be hyperplastic nodules,

2:15

sometimes functioning nodules.

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You do have a 10% incidence of about benign adenomas

2:22

and then the carcinomas are about 5% to 10%,

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and those are usually papillary and follicular carcinomas.

2:31

Thyroiditis accounts for about 1% to 5%.

2:33

And sometimes you will have lesions in the thyroid gland

2:36

that are secondary to parathyroid adenomas

2:39

or metastases to the thyroid gland,

2:42

or pure follicular or colloid cysts.

2:47

Again, as you get older,

2:49

you see that the incidence of nodularity within your thyroid

2:55

gland increases and increases. At autopsy specimens,

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in a person who is 70 years old,

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the rate at which you find thyroid nodules is 60%.

3:06

Now, these are nodules. These are not cancers.

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So in autopsy specimens of 70 year olds,

3:13

you'll probably find about a 15% rate of incidental papillary

3:17

carcinomas of the thyroid glands relatively

3:21

common incidental diagnosis,

3:23

but never spreads from the thyroid gland

3:26

into the adjacent tissues or lymph nodes.

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My colleague Jenny Hong,

3:31

who I mentioned previously in the publication on retropharyngeal space,

3:36

has done a really great job in creating an algorithm that is

3:40

supported by the American College of Radiology for

3:44

the evaluation of incidental thyroid nodules, or ITNs.

3:50

And this is from that ACR white paper.

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What they said was that if there are suspicious CT

3:56

or MRI findings of this incidental thyroid nodule,

4:00

those suspicious findings being spread outside the thyroids

4:03

capsule or adjacent lymph adenopathy, or

4:07

invasion into the trachea or esophagus,

4:10

that patient should be immediately evaluated with

4:12

thyroid ultrasound and subsequent

4:14

cytology or aspiration histology.

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If, on the other hand,

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it's just a nodule that is identified within the thyroid

4:24

gland, without suspicious CT or MRI findings,

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we separate them into those that occur in less than 35 year

4:32

olds and those that occur in greater than 35 year olds.

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Of those that are less than 1 cm in a patient less

4:41

than 35 years old, we usually don't do anything.

4:44

However, if it's greater than 1 cm,

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it will be evaluated with thyroid ultrasound, and based on

4:50

TI-RADS, the evaluation of the thyroid nodule by ultrasound,

4:55

it may or may not go on to aspiration cytology.

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However, in the patients who are greater than 35 year olds,

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we use a different marker, and that is 1.5 cm.

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If it's less than 1.5 cm in a 70-year-old,

5:10

we say no further evaluation.

5:12

If it's greater than 1.5 cm in a 70-year-old,

5:16

you would evaluate that with thyroid ultrasound.

5:19

And depending upon its characteristics on thyroid

5:21

ultrasound, it would get aspirated or biopsied.

5:25

So this is the age criteria as well as the size criteria that

5:31

the American College of Radiology recommends for

5:34

separating those that get evaluated

5:37

with ultrasound versus not. Now,

5:38

you notice that there's a little sidebar over here.

5:41

Those patients who have other comorbidities that are life

5:45

threatening, IE, they already have a nasopharyngeal carcinoma,

5:50

or they already have congestive heart failure that is

5:54

associated with a high morbidity.

5:56

Those patients,

5:57

we don't need to work up these thyroid glands because

6:00

patients very, very rarely will die from thyroid carcinoma.

6:03

They're more likely to die from their

6:05

life limiting comorbidities.

6:08

So this is the outline of the ACR white paper

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that Jenny is the first author on,

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and I recommend you create a macro for

6:18

your reports that describes this workup.

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And then when you find an incidental thyroid

6:24

gland on the CT scan of the neck,

6:26

you just fill in that template macro with the patient's age and

6:32

the size of the nodule to determine whether

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or not to evaluate with thyroid ultrasound.

6:37

The problem with thyroid nodules is

6:40

that based on the imaging features,

6:43

it's very difficult to predict which ones are going to be

6:47

benign and which ones are going to be malignant.

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So here we have two different patients.

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One of these has a malignancy and the

6:54

other has a benign nodule.

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Which is it?

6:57

Benign versus malignant?

7:00

Both have cysts with enhancing nodules.

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Let's look at this case.

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Both of these are solid nodules within the thyroid gland.

7:10

Is this benign or malignant?

7:14

That was benign.

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This one was aspirated and was a malignant mass.

7:19

Can't tell. This is by MRI scan.

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None of the features are diagnostic one way or the other.

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How about this one? We have a mass here,

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and we have a mass here.

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Which one of these two is the benign one?

7:33

Which one is the malignant one?

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This one was malignant in the left side.

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This one a little bit more of a diffuse process than

7:40

you might think of as multinodular goiter.

7:43

But the point is that on CT and MRI,

7:46

there are no really salient features of a thyroid mass

7:51

to determine whether it's benign or malignant.

7:53

Unless it has spread outside the thyroid capsule,

7:56

invaded the trachea or the esophagus,

7:59

or caused recurrent laryngeal nerve paralysis or

8:03

is associated with malignant lymphadenopathy.