The Use of Ultrasound in The Evaluation and Management of Head & Neck Squamous Cell Carcinoma - HD

Introduction and Disclosures

Hello, this is Jason Wagner.
I'm from the University of Oklahoma in Oklahoma City,
Oklahoma, and I am going to discuss the use
of ultrasound in the evaluation and management of head
and neck squamous cell carcinoma.
I have no financial disclosures
to make relevant to this talk.

Outline of the Talk

The outline of this talk is that we will begin
by reviewing the cervical lymph node stations.
Then we will discuss an overview of head
and neck squamous cell carcinoma as it
in particular relates to ultrasound imaging.
Then we will discuss the uses of ultrasound in head
and neck squamous cell carcinoma.
And finally, pathology that can mimic head
and neck squamous cell carcinoma.

Cervical Lymph Node Classification

To begin with the cervical node classification, I
strongly urge you to become comfortable with this
and to use this in reporting.
This is a widespread system that is used both
by imaging and by treatment physicians in head
and neck squamous cell carcinoma.
Although it may seem daunting,
it actually is relatively simple.
If you focus on four major landmarks that are all visible
with ultrasound, the first one that I will begin
with is right here, the posterior border
of the sternocleidomastoid,
which in my schematic over here,
is represented by this line.
Now, honestly, in the very inferior neck, the
it is the posterior border of the anterior scalene.
But what I use is just the posterior border of the
sternocleidomastoid,
and then just extend inferior from the mid neck.
If you are behind that line behind the posterior border
of the sternocleidomastoid muscle,
then you are in level five or the posterior triangle,
and that extends all the way back to the trapezius muscle.
If you are anterior to this line,
then you're in the other levels of the neck in this
location anterior to the posterior border
of the sternocleidomastoid.
Then the next key landmark is the inferior aspect
of the hyoid bone, something that is also
visible with ultrasound.
If your lesion is above this level,
then you're either in level one or level two.
An area of confusion,
at least in our ultrasound laboratory at university
of Oklahoma are lymph nodes that are in this area,
and the confusion as well.
Are they level one B or level two?
There actually is a fairly well-defined easy to locate
landmark to sort this out,
and that is the lateral most aspect
of the submandibular gland.
If the lymph node
or lesion in question is completely lateral
to the lateral border of the submandibular gland,
then the lesion is in level two.
If it is not completely lateral to the lateral border
of the submandibular gland, then it is in level one.
If you are below the level of the hyoid bone,
then you are either in level six
or the central compartment or level seven.
If you're down very low in the upper mediastinum,
or you are in the lateral compartment,
which is level three and level four.
The border between these compartments
is the medial border of the common carotid artery, which is
this line on this schematic.
If you are medial to the medial border
of the common carotid artery, then you're in level six
or the central compartment.
If you're lateral to the medial border
of the common carotid artery,
then you're either in level three or level four.
So those are the four major anatomic landmarks
for getting the major parts of the neck.
Again, that is the posterior border
of the sternocleidomastoid muscle, the hyoid bone,
and then above the hyoid bone, the lateral border
of the submandibular gland below the hyoid bone, the
medial border of the common carotid artery.
If you feel that you want to take this further,
then you can subdivide level one into one A and one B,
and the division there is the medial border
of the anterior belly of the digastric muscle.
If you want to divide level two into two A
and two B, then the key structure here is the lateral border
of the internal jugular vein.
Specifically, nodes that are well lateral of the internal jugular vein,
meaning they have a clear fat plane between them
and the internal jugular vein are two B,
otherwise it is two A, and then to divide level three
and level four or level five A
and level five B is the level of the cricoid.
In practice dividing level three
and level four is less important because most neck node dissections are going
to involve both of those,
but distinguishing between level three and level two
or level three and level six is very important as those are different surgeries.

Examples of Node Levels

So now some examples to apply that.
First we have this mass that is
medial to the submandibular gland and on a longitudinal view is between the mandible
and the submandibular gland.
So it's in this area right here, and
therefore is in level one or level one B.
The next example is this partially cystic metastasis squamous cell carcinoma, which this time because is in the right neck is completely lateral
to the submandibular gland, and
therefore is in level two
or specifically level two A right in this location.
The next example is another cystic metastasis from squamous cell carcinoma.
This is in the low neck.
You'll have to believe me that is below the level of the
hyoid and even below the level of the cricoid.
That makes sense because here is some thyroid tissue.
This is the common carotid artery, and
therefore this is lateral to the common carotid artery.
You can see the compressed internal
jugular vein right there.
Here is the overlying musculature.
This is in level four.
This enlarged lymph node that proved
to be benign is in level five.
You can see it here on the corresponding ct.
This is completely lateral to the posterior lateral border
of the sternocleidomastoid muscle, and
therefore is in level five.
Level six, or the central compartment to review is medial to the common carotid artery.
Here's common carotid artery. Here is trachea.
Another example in a different patient here is trachea.
Here is common carotid artery.
So these lesions here
and this lesion here are in level six, which is a common place to find locally recurrent thyroid cancer.
After thyroidectomy, now that we've reviewed the neck node levels, we will begin with a discussion,
an overview of head and neck squamous cell cancer.

Overview of Head and Neck Squamous Cell Carcinoma

This is a disease that affects about 55,000 people in the United States every year
with 12,000 deaths.
For comparison, thyroid cancer has an incidence
of about 63,000 new cases per year in the United States.
So these are about equally common.
However, the head
and neck cancer is far more lethal in that it causes at least six times more deaths per year than thyroid cancer.
Specifically, there is a five year survival of about 60 to 65% with head
and neck cancer as compared to 98% five year survival with thyroid cancer.
It is more common in males.
One thing that is important is
that this really is a heterogeneous group of diseases that each have unique biology
and a different clinical course,
and often different therapy based on the location
of the primary tumor.
Therefore, in the next series of slides, we're going
to discuss some of the common locations for primary tumors in head and neck squamous cell carcinoma.
This is a sagittal view from a ct
that we will use to mark the basic anatomic locations where tumors may arise.

Nasopharyngeal Squamous Cell Carcinoma

To begin with, nasopharyngeal squamous cell carcinoma,
this is actually fairly rare in the United States,
although it is somewhat common in Asia.
The treatment is usually with radiation therapy.
They're actually two different kinds.
There is the non keratinizing squamous cell carcinoma,
which has a strong association with Epstein-Barr virus infection.
And this is what's quite common in Asia.
It's highly radiosensitive
and has a pretty good five year survival as opposed
to the keratinizing squamous cell carcinoma,
which is not typically associated with EBV,
but is associated with smoking, radiation,
and other exposures, and has a fairly poor five year survival.
Another thing to remember is
that this is also a location where lymphoma certainly can occur
and can have similar radiographic features.
So here's an example of nasopharyngeal squamous cell carcinoma.
The primary tumors are difficult to visualize with ultrasound are usually visualized with CT MRI,
or in this case, PET ct.
But the nodal metastases can be visualized
with ultrasound, and nodal metastases from squamous carcinoma arising in the nasal pharynx tend to be level two
or possibly level three,
and occasionally to occur within the intraparotid lymph nodes.

Oral Cavity Squamous Cell Carcinoma

One of the more common primary sites that we see in the United States is oral cavity
squamous cell carcinoma.
This amounts for or accounts for 30% of malignant tumors of the head
and neck in the United States,
but it is a major worldwide health problem, six leading cause of cancer death in the world,
and in some parts of Asia accounts
for almost half of all cancers.
The risk factors involve things
that we put in our mouth, tobacco, alcohol,
and in some Asian countries other things such as betel nuts.
This involves the oral
or mobile tongue, which is the anterior two thirds
of the tongue anterior to the circumvallate papilla.
Of note, thickness
of a tumor greater than four millimeters increases the risk
of nodal disease,
and there have been reports
of using ultrasound directly on the tongue to measure thickness of the tumor.
These lesions tend to spread to level one B
or level two a lymph nodes, and it's uncommon for them to spread to level four,
level five in isolation.
The treatment for oral cavity cancer is
commonly with surgery.
Here's an example of a large mass in the anterior oral cavity.
This is visualized
with ultrasound from a submental approach.

Oropharyngeal Squamous Cell Carcinoma

Oral pharyngeal squamous cell carcinoma is a really a different disease, even though a lot
of them do involve the tongue,
but they are the posterior third of the tongue
or the base of tongue.
The other location is the tonsil tissue, and then there are other less common locations.
There are two flavors of this tumor, somewhat similar to pharyngeal cancer, except this is whether or not it involves HPV.
The HPV negative tumors are often keratinized,
and they involve smoking and drinking as risk factors
and tend to have a poor prognosis.
The HPV positive tumors are often,
but not always non keratinized.
They tend to be more poorly differentiated
histologically, however,
they do have a somewhat better prognosis,
and the strains of HPV are similar to the strains
that are commonly encountered in carcinoma
of the uterine cervix.
The treatment for this disease is most commonly chemotherapy
and radiation therapy.
Although there is a limited role for surgery,
and this disease commonly has bilateral nodal spread to level two
and level three at presentation level one,
lymph nodes are less common.
Here is an example of a large base of tongue tumor seen
by a submental approach with ultrasound.
These tumors are usually fairly easily demonstrated because they tend to be quite hypoechoic and stand out well from the intrinsic muscles of the tongue,
which tend to be fairly hyperechoic.
And here is a corresponding pet CT image
that shows the primary tumor
and nodal metastases, one of which is demonstrated here
with this ultrasound image.

Hypopharyngeal Squamous Cell Carcinoma

A less common primary location is
hypopharyngeal squamous cell carcinoma.
It's only about 4% of head and neck tumors.
They unfortunately,
generally present at an advanced stage, are related
to tobacco and alcohol.
It's unclear if HPV has a role.
These commonly spread two levels two, three,
and four, and treatment may be a combination of surgery,
chemotherapy, or radiation therapy.
Here is an example of a hypopharyngeal primary tumor here on the pet ct,
and again, on the ct with some nodal metastases, which are partially necrotic.

Laryngeal Squamous Cell Carcinoma

The other common location of primary tumor
that we see in the United States in addition
to oral cavity cancer.
Oral oropharyngeal cancer is laryngeal carcinoma.
This is one to 2% of adult malignancies.
It's three times more common in men
and has a strong association with smoking and drinking.
There are three subsets of laryngeal squamous cell carcinoma.
There's the supraglottic, the glottic, and the subglottic tumors.
They tend to spread to levels two, three, and four.
However, subglottic tumors can occasionally spread anteriorly to level six,
or the so-called delphian lymph node.
Although this is not extremely common, the treatment
for this is primarily radiation therapy with surgery
used in both very localized tumors
and in very extensive tumors.
Here is an example of a primary laryngeal carcinoma seen on the PET CT with a large level two nodal metastasis.
Now, ultrasound, of course, is not the primary way
of imaging the vocal cords.
In fact, these are usually just visualized endoscopically.
However, you often can actually see the vocal cords with ultrasound.
And here you see a large mass hypoechoic on the right vocal
cord with impaired mobility of the cord.

Cervical Esophageal Squamous Cell Carcinoma

Another site of primary disease is the cervical esophagus, which tends when it has cancer to be squamous cell carcinoma, as opposed to the lower thoracic esophagus, which often will have an adenocarcinoma.
This is not a terribly common disease,
but it is a very lethal disease with a bad prognosis, five year survival of only 12 to 33%.
This can spread to the cervical lymph nodes,
but it also can spread to the upper mediastinal lymph nodes.
And treatment can involve all
of the modalities.
Here is an example of a primary upper cervical
carcinoma that unfortunately recurred with a lymph node here that you can see on these ultrasound images.
You can see it has mass effect on the internal jugular vein.

Summary of Nodal Metastases Locations

So, to summarize, head
and neck carcinoma, the usual locations
of nodal metastases are
in level one if it is an oral cavity cancer.
Otherwise, most of the metastases occur in level two,
level three, and a little less commonly Level four.
Level six is uncommon,
but can occasionally occur in subglottic
laryngeal carcinoma.
Level five is uncommon, except in extensive disease.

Skin Primary Squamous Cell Carcinoma

Another location of squamous cell carcinoma is skin primary, and where this becomes of greater clinical significance
and possibly becomes a lethal disease is
with extensive tumors that can occasionally produce perineural invasion
and creep along the nerves of the head and the skull base.
This occurs in three to 6%
of cutaneous squamous cell carcinomas,
and in a smaller percentage
of cutaneous basal cell carcinomas.
A midface location is thought to be a risk factor for perineural invasion, most commonly involves cranial nerves five and seven,
and the symptoms can include formication,
which is a feeling of ants crawling under the skin,
numbness, pain, facial weakness, in midface location,
recurrent disease, male gender are all risk factors for perinatal invasion.
And when perineural invasion occurs, there is a five year
disease free survival of only 51%.
It also increases the risk of local nodal metastasis.
And MRI with contrast is the preferred imaging modality.
Here is an example of a small primary
squamous cell carcinoma of the skin in the midface
and a 52-year-old male.
Here you can see the high resolution ultrasound image
of this primary tumor.
Unfortunately, he presented with numbness
and these images through the parotid demonstrate branching hypoechoic linear structures, which are the branches of the facial nerve.
Usually you cannot see these branches.
You can see them here
because of the extensive perineural tumor.
To summarize, metastasis in the head
and neck from a skin primary can occur anywhere, but has a propensity to involve the parotid
and intraparotid lymph nodes.
And here's another example.
This is a metastatic Merkel cell carcinoma of the skin.

Distant Primary Carcinomas

The other type of squamous cell carcinoma that is encountered in the neck is squamous cell carcinoma,
or for that matter, any other type of carcinoma
that comes from a distant location, usually inferior
to the clavicle such as lung cancer,
or in this case, metastatic vulvar cancer.
The significance here is that these usually
involve the supraclavicular lymph nodes in the low neck.
To summarize with this slide,
they usually occur near the clavicles
as the initial presentation
of metastasis from a distant primary.
They can become more extensive
and creep up the neck, but the most common or the most extensive disease usually remains in the
supraclavicular fossa.

Thyroid Cancer Nodal Spread

Thyroid cancer certainly spreads
to lymph nodes in the neck, tends
to involve levels three
and four, as well as levels six and seven.
In an untreated neck, isolated metastasis to level two
or to level five is uncommon in an untreated neck except in extensive
disease throughout the neck.
Once the neck has been treated, though, isolated recurrences in level two
or level five can occur,
but still remain uncommon, disease involving level one is quite rare in extensive disease.

Uses of Ultrasound in Head and Neck Squamous Cell Carcinoma

So how do we use ultrasound in head
and neck squamous cell carcinoma?
While there are multiple uses
that have been validated in the literature,
including evaluation of neck masses,
staging in select patients, usually patients with
what appears to be a limited stage oral cavity cancer post-treatment surveillance is used in highly selected patients, often again with oral cavity cancer that was not where the neck was not treated in our practice.
We also use this for other things, of course, thyroid carcinoma, but we also use it for certain melanomas
of the head and neck and certain higher risk skin cancers of the head and neck.
And then probably the most common use,
at least in our practice, is problem solving,
particularly problem solving
after a pet ct that has findings
that are unclear how to translate into patient management.

Ultrasound Protocol

So what protocol do we use when we're doing ultrasound
of the head and neck in these cancer patients?
We have an extensive protocol,
a comprehensive protocol that we scheduled
for a 45 minute time slot.
This was very important when we got started doing this.
And in patients who have a lot of abnormalities,
these exams still take 45 minutes, occasionally longer.
As we've gotten better at these and increased the number that we do, many
of these exams now take less than 45 minutes, particularly if there are few
or no major abnormalities.
One thing that we do at University of Oklahoma,
which may be a little bit unusual, is that we tend
to scan these patients sitting up at least 45 degrees,
sometimes 75 or 85 or 80 degrees upright.
We do still hyperextend the neck
by placing a rolled towel
or a pillow behind the shoulders to the extent the patient is comfortable.
So why do we sit these people up?
We found that in our patient population with cancer, which many times are older
and larger people, that they're far more comfortable in this
position, particularly those who have sleep apnea use CPAP
whenever they recline, they can become extremely uncomfortable when placed in a
supine position with their neck hyperextended.
And even if they are safe
and maintaining their breathing, they tend to be very find it difficult to cooperate with the examination.
They tend to be breathing heavily and squirming.
And so we have found that if we sit them up
that they are far more comfortable hold still better,
and tolerate the exam better.
And when they are sitting up,
we scan facing the patient standing at the bedside.
This upright positioning also makes gravity
your friend, particularly for low neck
and substernal lesions,
because with gravity, the shoulder girdle, clavicles
and anterior chest wall soft tissues fall down,
whereas the neck tissues that we're trying to image tend
to fall down less.
So it makes it a lot easier
to see these low neck lesions.
We do occasionally do the more traditional flat supine
imaging with the neck hyperextended, primarily for young
or thin patients who tend to tolerate
that positioning much better.
We do long and transverse images in each nodal station, but we only measure large
or abnormal appearing lymph nodes.
And when I say large, I generally mean lymph nodes
that approach or exceed one centimeter in short axis.
We use cine sweeps that are recorded in the PACS for
abnormal appearing lymph nodes,
or particularly clusters
of enlarged lymph nodes in which we're not going
to measure all the lymph nodes.
Just maybe a representative one
or two for our non comprehensive protocols, such
as when we're just looking at the thyroid
or when we were asked to do a biopsy, for instance,
a thyroid biopsy, we always do at least a brief sweep of all
of the nodal basins to make sure there are no abnormal lymph nodes,
because sometimes it will change our management in these patients.

Examples of Ultrasound Applications

Here's an example of a case and how we apply.
Some of the things I spoke about recently about the where nodal metastases tend to occur.
This was a 71-year-old female with a history
of squamous cell lung cancer who finished treatment about a year ago with no current evidence of recurrence in the chest.
She presented with a new palpable essentially painless right neck mass.
And when we scan this, this looks like a metastatic squamous cell carcinoma.
You can see an irregularly bordered hypoechoic solid mass that appears
to have extracapsular spread
or just extension right out into the adjacent soft tissues.
But when we scanned the remainder of the neck, it we did not see any other evidence
of nodal mets lower in the neck.
Specifically, there was no evidence of disease in the supraclavicular fossa.
And as I said previously spread from a primary
below the clavicle, such as lung cancer tends
to be in the supraclavicular fossa.
So this isolated level it's really level two, we had,
this is incorrectly labeled level three,
a isolated level two metastasis is uncommon for a extra neck
or a infraclavicular primary,
but it's very common for a head and neck primary.
So we looked some more, and we found this supraglottic mass
that you can see in this scan as we go down to the cords.
And here in ct here is the primary,
or here is the nodal metastasis,
and here is the supraglottic primary.
This is of great importance for this patient
because since this is a new neck primary, it can be treated
with curative intent as opposed to
a spread from lung cancer, which would be limited
to palliative therapy.

Here's an example of evaluating a mass and problem solving.
This is a 37-year-old male with no history of cancer, who
reported a firm parotid mass
after a 150 pound intentional weight loss.
This gentleman actually got on the treadmill
and did what a lot of us need to do and lost some weight,
and now he feels this rock hard mass.
And we did ultrasound in transverse and long.
You can see an echogenic smooth interface with
complete acoustic shadowing.
Below it, it looks like a bone,
because in this case, it is a bone.
It is C one.
We looked at a prior neck ct the patient had had, which was also done to evaluate this mass,
but was reported as normal.
And you can see that there is a little bit
of offset of C one.
It's a little bit asymmetrically positioned to the right.
Just to confirm, we swept up and down
and we see the vertebral artery as it curls around the edge
of C one.
So obviously we did not perform any biopsy in this case, and we just reassured the patient.

Another example of problem solving
of a mass is a 70-year-old male with a history of radiation therapy for laryngeal squamous cell carcinoma
multiple years ago, who also had a history
of lung cancer who presented with a new palpable mass in the submandibular region.
And this is the mass. And what this is,
is an enlarged inflamed submandibular gland.
So the question is, why?
And we followed this anteriorly,
and we found that the duct
of the submandibular gland was enlarged.
And as we swept further anteriorly,
we found out why this was a new primary floor
of mouth cancer that was obstructing the duct
and was invading the mandible.

Staging of Head and Neck Squamous Cell Carcinoma

So staging of head and neck squamous cell carcinoma.
In the TNM staging system, the T stage refers to the primary tumor.
This is not usually where ultrasound gets involved.
This is usually staged by a combination
of physical examination and endoscopy, plus
or minus contrast CT or PET ct.
And many of these patients do get a pet CT except for localized oral cavity and glottic cancers.
I'm not gonna go extensively into the T staging because it is unique to each primary site
where ultrasound has a lot to offer, is the N stage,
and here is the N staging for head and neck cancer.
N zero no mets, N one,
a single ipsilateral met less than three centimeters
into a single ipsilateral node between three
and six centimeters, two b multiple ipsilateral nodes,
but none are greater than six centimeters.
N two c, contralateral
or bilateral lymph nodes, none greater than six centimeters
and not commonly seen in three a,
a single node greater than six centimeters.
Extracapsular spread is not technically part of this,
but is a very important finding when the tumor is just spreading out of the capsule
of the lymph node into the adjacent tissues.
As we'll discuss in just a few minutes.

N Staging with Ultrasound

So a little more detail on N staging ultrasound has a sensitivity of 63 to 97%,
and a specificity reported between 74
and a hundred percent at staging of these cancers.
By determining abnormal
or suspicious lymph nodes, metastatic nodes tend
to be rounder than normal nodes
and to lack a an echogenic hilus,
there is no consensus on size criteria, unfortunately.
And in our practice, we find the size
of the lymph nodes to be the least helpful.
For instance, look at this. This is a very large lymph node.
However, it maintains a normal nodal morphology.
It looks kind of like a big kidney.
You have a fairly uniform hypoechoic fairly homogeneous cortex, a visible echogenic hilum, and a hilar pattern of blood flow.
In contradistinction.
There is this lymph node, which is barely,
if at all, enlarged.
However, it is more echogenic.
It has no discernible echogenic hilus, it is quite rounded, and this was
metastatic squamous cell carcinoma.
The other part of evaluating this lymph node,
however, was the history.
The patient had known squamous cell carcinoma of the oral cavity, and this is in an expected nodal basin.
Here is an example of metastatic carcinoma
with a non hilar pattern
of blood flow at surgery.
In surgical series, 46% of metastatic lymph nodes
of squamous cell carcinoma are found
to be less than 10 millimeters.
Another reason why size is not very helpful, cystic nodes tend to suggest necrotic metastasis.
The non hilar pattern of blood flow as shown here,
is not commonly seen,
but is highly suggestive of metastasis.
However, very importantly in squamous cell carcinoma,
the absence of a color doppler signal is
not a helpful finding.
You often can't see that in metastasis
and ultrasound guided fine needle aspiration has a
sensitivity of 80, 90, 98%,
and a specificity of 95 to a hundred percent, and is a very useful test when
concerned about a lymph node.
And importantly, when nodal metastases are present in head
and neck squamous cell carcinoma,
they reduce patient survival by 50%.
This is actually metastatic thyroid cancer,
which tends to be more hypervascular than metastatic
squamous cell carcinoma in the neck.
And it nicely shows the non hilar pattern of blood flow.

So here's an example of staging a patient with head
and neck squamous cell carcinoma.
This was a 54-year-old female who was thought clinically
to have a small limited oral tongue cancer,
the lateral aspect of the tongue that had been proven with biopsy.
And the patient was being set up for surgical resection
of this tumor, which is the standard therapy
for our oral cavity cancer.
There were no palpable nodes on examination,
but the patient was obese.
So the surgeon sent the patient for an ultrasound as the only preoperative imaging test for staging, and we found a single enlarged ipsilateral lymph node
that still had a retained visible hilum.
This lymph node is suspicious,
however, a reactive lymph node is also possible in a patient
who's recently had a biopsy.
So we did a fine needle aspiration,
and on the preliminary cytology
and on the pap stain, we see abnormal keratinizing cells consistent with metastatic squamous cell.
So when the patient had her primary tumor removed,
she also had a neck dissection.
And fortunately, this was the only lymph node involved here
on h and e, you can see the preserved rind
of lymph node tissue
and then the large metastasis focus
of squamous cell carcinoma.
Fortunately, for this patient,
there was no extracapsular spread.
There was no spread outside the bounds of the lymph node.

Extracapsular Spread

But speaking of extracapsular spread, here is an example
of a 68-year-old female who presented with a left neck mass,
no history of cancer,
but you'll notice that this mass is solid, it's irregular,
it has ill-defined border.
You can just kind of see the tumor just creeping right out
into this, into the overlying sternocleidomastoid muscle.
This is a very important finding when you see it,
because it is a strong prognostic factor,
reducing patient survival by an additional 50%.
And in this case, as is not rare,
this patient presented with a mass here, and no known or symptomatic primary,
but on pet ct, a small primary in the tonsil was discovered.
Here's another example of extracapsular spread in a level two lymph node in a patient with tongue cancer, you can see the tumor just creeping out
fingers of tumor creeping into the overlying muscle.
And here with gentle pushing on the muscle,
you can see the deep fibers of the sternocleidomastoid muscle not moving normally due
to the direct extension of tumor into the muscle.
And here you can see the pet ct, primary tongue cancer
and the nodal met that we're imaging here.

Post-Treatment Surveillance

Ultrasound is also used for post-treatment surveillance.
And one of the reasons for this is
that the optimum treatment of a patient
with limited stage surgically resectable oral cavity cancer, and a clinically negative neck remains controversial.
Many patients undergo elective neck dissection,
although up to 75% of patients have no tumor at pathology from these neck dissections.
Some centers have tried sentinel node biopsy,
but for a number of reasons, that is not used
commonly in head and neck squamous cell cancer.
So another option is to do a ultrasound
and if you don't see anything, then
to just closely follow the patient
after treatment of their primary tumor.
And if we do this, we often do very frequent scans,
and in this case, we have a very low threshold for biopsy.
Basically we FNA, anything that grows
or is it all funny looking?
And we pay particular attention to the expected
nodal basins, which in oral cavity cancer would be the ipsilateral one B, and level two stations.

So here are examples of metastatic squamous cell carcinoma.
You can see them all labeled here as well
as this and this.
And you can see that these masses are hypoechoic, but not extremely hypoechoic in general.
They can be fairly well-defined,
they can be ill-defined.
These often have minimal or no internal blood flow.
Here are more examples of metastatic squamous cell carcinoma.
This one has a small area of internal cystic change or necrosis.
Here's another example, yet another example,
and again, another example of metastatic squamous cell carcinoma.

Other Uses of Ultrasound

So how are other ways,
or what are other ways that we use ultrasound?
One of them is problem solving.
This is an example of a patient who had been treated with chemo
and radiation therapy for tonsil squamous cell carcinoma, and had this pet ct with a lot of areas of activity that tended
to follow the digastric muscle and the scalene muscle.
So we were suspecting
that this was just asymmetric muscular activity.
However, due to the intensity
and a little bit of maybe nodularity, we did an ultrasound to carefully scour these muscles.
We did find asymmetry of the digastric muscles
probably related to therapy, but we found no mass and
therefore no biopsy was performed.
And the patient has been fine undergoing further surveillance.

Another example of problem solving.
This patient, 48-year-old, who had been treated
with chemo and radiation therapy
for tongue squamous cell carcinoma had this pet ct,
which is highly suggestive of recurrent tumor
that is invading and eroding the hyoid bone.
However, a surgical biopsy of this area was negative.
So we did a an ultrasound.
We see a mass that
actually in this case was hypervascular,
which is not terribly common for squamous cell carcinoma,
but does occur, and we biopsied this mass being careful to stay out
of the airway, which is right here.
And it showed recurrent squamous cell carcinoma.

Other things that you can see if you're looking at these
post-treatment patients, you can see various types
of reconstructions, including the neopharynx
after laryngectomy, which you can see here,
you can see the collapsed cavity in the center of it
and the surrounding fatty tissue.
This was a flap reconstruction, the floor of mouth.
And if you follow this cine loop, you can see
the tissues extending all the way up from the chest
because this was a piece of pectoralis muscle
that is swung up into the floor of mouth.
It's important to understand these reconstructions to avoid interpretive errors.
Here's another example of
where an interpretive error could be made.
This patient has a neopharynx
and then has this area of pet avidity next to it, which on ultrasound was consistent with the diagnosis
of a healing fistula post-surgery.

Here are some examples of fluid collections.
This was just a benign post-op fluid collection most
commonly seen fairly soon after surgery.
This, unfortunately, was a recurrent necrotic nodal squamous cell metastasis.
And so if these don't go away, they sometimes need
to be sampled to make sure that it's not residual or recurrent squamous cell carcinoma.

Pathology Mimicking Squamous Cell Carcinoma

One thing that can cause some confusion is the uncommon,
but occasionally occurring new presentation
of a branchial cleft cyst in an adult.
And this is such a case of this 44-year-old male with this cystic lesion here seen on ultrasound.
But here is a 45-year-old male
with a fairly similar appearing cystic lesion in nearly an
identical place with a somewhat similar ultrasound appearance.
This was necrotic squamous cell carcinoma
with no primary ever found.
These have a can have a overlapping appearance
by CT and ultrasound.
And so in our institution, we treat these as squamous cell carcinoma until proven
otherwise in adults that are old enough
to have squamous cell carcinoma.
And in the uncommon case is they end up being benign cyst.
Well, good for the patient. One thing that does come up fairly commonly are the cystic
or necrotic liqui changes in squamous cell carcinoma.
Here's a good example. This is usually true necrosis with liquification.
As opposed to metastatic papillary thyroid cancer, which tends to be more of a cyst formation by the neoplastic cells
and has more of an ovary in the neck type look as opposed to
squamous cell carcinoma, potential mimic of squamous cell carcinoma.
Or a another way of putting it
as a diagnostic challenge are patients
with residual masses after therapy.
And the question is, is there any viable tumor?
This is commonly encountered in people with particularly oral pharyngeal cancer,
which may have large nodal metastases that are not treated
with surgery initially, but treated with chemotherapy
and radiation therapy, particularly if the pet CT is
obtained too soon, you will still see a residual mass
with some pet activity.
The question is, is there a viable residual tumor
or is it just killed disease
that hasn't completely gone away?
I will tell you that this is a difficult imaging distinction, and oftentimes we have to biopsy these.
This is one case where fine needle aspiration usually
doesn't work because a pathologist cannot tell dead squamous cells from residual viable tumor easily on FNA.
So in these cases, we often do core biopsy, and in this case, it ended up being no obvious viable residual tumor.
And this patient was further followed
and the residual mass essentially went away.

Other mimics that can be encountered include a
post-traumatic neuroma, which occurs not infrequently.
Usually it's more of a delayed five, 10
or more year after surgery.
And it is just a proliferation of cells not really a true neoplasm at the end of a transected nerve.
These can be biopsied,
however they are painful at times during biopsy.
Here is another example of a neural tumor, a schwannoma,
which is occasionally encountered in the neck.
You can also encounter carotid body tumors.
These occur in a fairly similar location
to the usual level two
or level three metastasis of squamous cell cancer.
However, these are within the carotid sheath as opposed
to adjacent to the carotid sheath.
Although sometimes that distinction can be a challenge
as metastatic squamous cell cancer can surround the carotid vessels these tumors classically when their carotid body tumors splay the bifurcation
of the internal and external carotid arteries,
they're mostly solid, but can have some cystic change
and tend to be hypervascular
with a low resistance flow pattern.
A closely related vagal paraganglioma is shown here.
This is not necessarily quite as vascular a tumor,
and shows the cystic changes
that can occur in a paraganglioma.
Classically, these displaced the carotid vessels anteriorly rather than
splaying the bifurcation.
However, that anatomic arrangement can be difficult to demonstrate.
Of course, things that can occur anywhere in the body can
occur in the neck, such as this example
of an epidermal inclusion cyst.
These classically have dermal contact.
They've been described as having a pseudo testis echogenicity or echo pattern internally.
They classically have enhanced
through transmission edge refractive shadowing,
and they should have no internal blood flow
unless they rupture.
If these rupture, they become a more difficult diagnosis
because they can be an ill-defined almost infiltrating
looking structure, but they still should involve the dermis.
And ideally you can get a history of a mass
that was not very symptomatic,
that subsequently became symptomatic.
You can commonly encounter accessory parotid tissue at the
anterior aspect of the parotid, a along Stensen's duct,
usually at the superficial border
of the masseter muscle.
And here you can see an example as we come out
of the parotid, and then here is the accessory tissue.
This can grow neoplasm just like parotid tissue can.
But it's important not to mistake this for a mass.
And then rarely you will see something like this in the
face, which here is a CT correlate.
And this was a silicon granuloma from a augmentation injection.

Take Home Points

So some take home points.
Ultrasound plays a valuable role in the management
of head and neck squamous cell carcinoma, particularly in the assessment of nodal disease and problem solving as well as guiding biopsy.
The location of the primary tumor determines the most likely
location of nodal disease in an untreated neck.
Once the neck has been treated,
those rules do not necessarily apply,
and multiple benign conditions can
simulate squamous cell carcinoma.

Multiple Choice Questions

So now, finally, I'm gonna give a few multiple choice questions for you to evaluate if you've internalized some of this information.
So the first question, A patient has newly diagnosed base
of tongue cancer and presents for nodal evaluation.
What is the most likely place to find
nodal metastasis in new base
of tongue cancer without prior treatment?
So the answers are a level two B, level three
or four C, level five D supraclavicular fossa,
and the answer is level two.
Level one B would be possible,
although that's usually more common in oral cavity
or mobile tongue cancer.
Level three and level four are also possible.
However, level two is more common.
Level five and the supraclavicular fossa would be
uncommon in this situation.

So similar question,
but now we're going to say
that a patient has newly diagnosed thyroid cancer in an untreated neck and presents for nodal evaluation.
What is the most likely place to find nodal metastases?
Again, level or a level two B, level three
or four C, level five
D the supraclavicular fossa.
In this case, the answer is level three or four.
Of course the other answer would be level six,
which is another common place to find a metastasis
of thyroid cancer.

And the final question, the patient has newly diagnosed lung
cancer and presents for nodal evaluation of the neck.
What is the most likely place to find nodal metastases?
A level two B, level three slash four,
C level five, or d the supraclavicular fossa?
In this case, the answer is the supraclavicular fossa.
Because primaries originating
below the clavicles when they spread to the neck tend
to be most commonly in the low neck
or the supraclavicular fossa.

Conclusion

So I thank you for your attention
and hope you found this to be a valuable experience.