Ultrasound of the Neck: There's More to See Than Thyroid Nodules - SD

Introduction

Hi, my name is Michelle Milani.
I'm from Santa Monica, California.
I am Chief of Women's Imaging at Cedars-Sinai Medical Center, and I'm also the Vice Chair of imaging at West Los Angeles VA Medical Center.
My lecture today will be on ultrasound of the neck.
There's more to see than thyroid nodules.
Today I'll be speaking about ultrasound of the neck.
There's more to see than thyroid nodules.

Educational Objectives

The educational objectives for this lecture include differentiating masses in the thyroid bed in patients with prior thyroidectomy.
We're also going to review the features of abnormal neck nodes in patients who have differentiated thyroid cancer, both medullary thyroid cancer and papillary thyroid cancer.
I'll review some of the more common cystic lesions in the neck, and also, we'll discuss some of the limitations of ultrasound in imaging non nodal masses of the neck.
Today we're gonna not be speaking about thyroid and parathyroid, and salivary glands, which have been covered in other lecture series.
I will discuss, however, cervical lymph nodes in patients with differentiated thyroid cancer and how they present both normal and abnormal.
I'll discuss masses that you might see in the postoperative bed in patients who've undergone prior thyroidectomy for differentiated thyroid cancer.
I'll discuss some of the more common cystic lesions in the neck.
And also briefly describe some of the non nodal masses of the neck that you may encounter during these scans.

Reasons for Scanning the Neck

First of all, why do we scan the neck?
I think most people who've trained in radiology have learned that CT and MRI are far superior in imaging the neck in patients with different head and neck cancers.
First of all, there's been a huge boom in imaging over the last 10 to 15 years, and we've seen an increase in the number of incidental thyroid lesions detected on PET CT scans, chest CT scans, cervical spine and neck CT scans and MRIs, and also, patients undergoing carotid ultrasound for screening.
These patients have come to us for imaging to try to determine if these thyroid lesions are clinically relevant.
Our latest practice guidelines from the ACR and AIUM for the performance of thyroid and parathyroid ultrasound have a statement which states abnormalities of the adjacent soft tissues when encountered, such as abnormal lymph nodes or thrombus veins should be documented.
When we're scanning these patients and we see these incidental findings, we need to know what we're looking at and we need to describe them in the report.
Why else do we scan?
First of all, the most recent revised American Thyroid Association guidelines from 2009 state that pre-op thyroid imaging of patients to look for nodal metastases in the jugular chain is important.
And also, a certain population of postoperative patients will undergo routine screening of the neck with thyroid ultrasound.
Here's just the recommendation 48 A.
This document, the revised American Thyroid Association guidelines from 2009 is quite lengthy.
Several of the recommendations pertain to imaging of the neck and this particular guideline, number 48 a states that following surgery, cervical ultrasound to evaluate the thyroid bed and central and lateral compartment should be performed at six to 12 months, and then periodically, depending on the patient's risk for recurrent disease and thyroglobulin status.
And this receives a recommendation B, which is actually a high level recommendation.
The recommendations range from being graded A through F and B is quite a strong recommendation.
They recommend that these patients undergo routine imaging, and the interval between ultrasound imaging will be determined by the pathologic behavior of the lesion and also the nodal status, whether the patients had central or lateral compartment malignant adenopathy at the time of their initial surgery.

Pre- and Postoperative Ultrasound in Thyroid Malignancy

Let's talk about pre and postoperative ultrasound and thyroid malignancy.
Again, I stated previously that ultrasound is superior to CT and MRI in the evaluation of local metastatic disease to the neck.
And this is specifically in patients with differentiated thyroid cancer, other head and neck cancers.
This does not apply.
What we need to do in this patient population is evaluate the thyroid bed for recurrence and local metastases.
The thyroid bed is also called the central compartment, and is also called level six papillary thyroid cancer.
And medullary thyroid cancer will metastasize to the ipsilateral jugular chain, and the jugular chain of nodes includes levels two through four.
And I put a little asterisk here just to remind you that when you're scanning these patients, their thyroid gland has already been removed.
And I would say that most patients do not remember which side their thyroid malignancy was on prior to having the thyroid gland removed.
In addition, there's a small percentage of patients reported cases in the literature which discuss contralateral metastases in thyroid cancer to the opposite jugular chain.
And finally, lots of patients may not realize that even though they had a thyroid malignancy on the right side, they might have had a micro papillary carcinoma when the thyroid was eventually removed in the opposite side.
Sometimes patients actually have bilateral disease.
We need to be really vigilant and look at both jugular chains, even if we have an idea that the patient had their malignancy on one side or the other.
Ultrasound of the neck has been deemed to be more sensitive than whole body iodine scans and serum thyroglobulin levels in detection of recurrent papillary thyroid cancer in the neck.
At our institution, we no longer perform whole body iodine imaging for follow up of patients with thyroid malignancy.
And also this has been removed from the current ATA guidelines.

Masses in the Thyroid Bed: Differential Diagnosis

The differential diagnosis for neck masses in the thyroid bed in patients with papillary and medullary thyroid cancer includes local recurrence or central nodal metastases and postoperative change.
Other lesions that are more red herrings that you won't see as often are cervical thymus typically seen in the younger patient population, and rarely, you might see a Zenker's diverticulum.
Other lesions, which I won't show you images of today, include central compartment lymph nodes, normal lymph nodes.
Patients with Hashimoto's can have enlarged hypoechoic nodes, and patients can have reactive nodes in the central compartment for other reasons, regrowth or residual thyroid tissue can be seen if the surgeon has done an incomplete thyroidectomy.
Remember when we talk about a total thyroidectomy, it's really a subtotal thyroidectomy for the purposes of decreasing morbidity to the recurrent laryngeal nerve.
The surgeons are usually compelled to leave small amounts of thyroid tissue behind.
Some of this thyroid tissue can regrow depending on the extent of the surgeon's ability to remove the thyroid.
Sometimes certain patients will have more residual thyroid tissue, and a lot of patients these days are not undergoing radioactive iodine therapy.
Those ATA guidelines have new recommendations on who is eligible or who should be getting radioactive iodine.
In this case, we may see more and more of these cases of residual thyroid tissue and rarely patients.
You might see a lesion in the thyroid bed, which will turn out to be an enlarged parathyroid gland.
I would say that most of these patients have elevated calcium and parathyroid hormone and tend to be symptomatic, and it's known prior to them coming for their scan.
But occasionally you'll see one of these, the thyroid bed.
I'll just show you this schematic here superimposed on a real patient.
And then this drawing, the thyroid bed is also called compartment six or the central compartment, and is basically all the tissues between the two carotid arteries.
Once the thyroid gland is removed, the carotid artery tends to be opposed more closely to the trachea.
And you're gonna be looking for masses in this thyroid bed.
If the patient has, if the surgeon has not removed all of these central compartment nodes or the majority of these central compartment nodes, small masses in the thyroid bed may represent these residual nodes.

Recurrent Thyroid Cancer

Recurrent parathyroid cancer in the thyroid bed tends to be circumscribed up to 70% of cases.
It's typically hypoechoic with smooth margins.
Most of the lesions you'll be able to detect color flow.
Occasionally you'll see these parallel hyperechoic lines, which can mimic calcifications, but if you put color on, these are usually the walls of the blood vessel.
You may or may not see calcifications or cystic change, and those features are more suggestive of recurrent thyroid cancer.
The differential diagnosis would include postoperative change and different findings of postoperative change include fat necrosis and suture granulomas.
In this case, color flow in this lesion highly suggests that it's recurrent papillary thyroid cancer in the thyroid bed and not postoperative change.

Postoperative Changes and Suture Granulomas

Suture granulomas have been described in the literature.
They're typically small hypoechoic lesions.
They also tend to be circumscribed.
They have echogenic foci that may mimic microcalcifications.
The echogenic foci typically have a paired appearance and maybe more irregular in shape and larger than typical microcalcifications seen in papillary cancer recurrence.
And then again, the hallmark of these is they will not have color flow.
Even though these two paralleled echogenic foci, you may wonder if they're the wall of a blood vessel when you put color on.
There's no flow in this.
This was a small suture granuloma with a little suture material right here.
This is the same patient again.
He was a patient with a history of papillary thyroid cancer who came back with an elevated thyroid globulin level.
It had been creeping up greater than two, and it was now 2.8.
He had this lesion, which we were quite confident, was a suture granuloma.
And he also had this second lesion pretty well circumscribed with central color flow.
And this was his local papillary thyroid cancer recurrence.

Cervical Ectopic Thymus

Cervical ectopic thymus is typically seen in the younger patient population.
A lot of our younger patients in their twenties and thirties who can really hyperextend their neck.
We will see cervical ectopic thymus or even normal thymus that extends up into the neck because they have a great ability to hyperextend.
Just going back to some embryology, the thymus develops from the third and fourth pharyngeal pouches typically descends in gestation between the sixth and 10th week of life.
From the angle of the mandible into the sternum, into the mediastinum, any interruption of the descent can lead to an abnormal position.
The most common locations of that abnormal position include the lateral neck or the suprasternal location.
In children, sometimes the cervical ectopic thymus can present as a visible or a palpable mass.
A lot of times when there's Valsalva maneuver, if the child is crying, or occasionally these can be seen incidentally, for example, when imaging the thyroid gland, often what we're seeing is not cervical ectopic thymus, but superior herniation of the normal thymus into the neck in those patients who have a great ability to hyperextend the.
The typical appearance of the thymus is that it's often well circumscribed and hypoechoic with these echogenic linear branching lines and septations, which represent septations of connective tissue and blood vessels.
This is the inferior pole of the thyroid.
This is the inferior thyroid artery, and this is superior extent of the thymus adjacent to the lower pole.
If we angle the transducer down, we can see this extending down into the mediastinum.
Here's another image of cervical thymus.
In this case, it's projecting posterior to the lower pole of the left thyroid lobe.
In the transverse image, notice that this is the carotid.
The jugular is compressed anteriorly, and this is projecting lateral to the carotid.
In certain circumstances, it could mimic a jugular chain lymph node.
Here's a patient, a 16-year-old with a neck mass that was highly suspicious and turned out to be papillary.
Thyroid cancer has lots of tiny echogenic foci, which represented microcalcifications or psammoma calcifications.
When we were looking preoperatively to see if this patient had metastatic disease, we saw this fairly well circumscribed oval nodule in the inferior neck.
It projected lateral to the jugular vein and carotid artery, and was mimicking a level four metastatic lymph node with these echogenic foci.
And this was superior extent of the thymus into the lateral neck.
Here's a 26-year-old patient whose thyroglobulin had been going up and the endocrinologist was worried about a recurrence of papillary thyroid cancer.
He saw this hypoechoic lesion with tiny echogenic foci, which we were quite confident represented the thymus.
It was extending up into the region of the sternal notch.
And when we scanned the patient's thyroid bed, we saw this circumscribed hypoechoic mass with central color flow that we determined was highly suspicious for recurrent papillary thyroid cancer in the thyroid bed.
And we did not see jugular chain metastases in this young patient.
You can biopsy these lesions.
It was a tiny lesion just a few millimeters.
We did not get positive cytology on this from the FNA.
However, we routinely send the washout of these FNA, so we'll spread the FNA specimen on a slide, and then we'll rinse the needle tip in one to two ccs of saline and send it out to the lab for thyroid globulin analysis.
In this case, the thyroid globulin was positive.
The patient had received prior radioactive iodine, so she's unlikely to have any normal thyroid tissue.
And this was recurrent thyroid cancer in the thyroid bed.
Just a little red herring alert.
This is not an uncommon finding, but occasionally you can see intrathyroidal thymus.
And this is a case of intrathyroidal thymus.
If you were to see this case in your lab, you would be highly suspicious that this was a papillary thyroid cancer, a hypoechoic lesion with microcalcifications, but it turned out to be intrathyroidal thymus.

Zenker's Diverticulum

I'll talk briefly about Zenker's diverticulum.
These lesions can mimic malignant thyroid nodules on ultrasound.
They're uncommonly seen.
I've seen about three cases, and I've seen cases after they've been biopsied by one of my colleagues.
It typically presents as an isoechoic or hypoechoic mass with internal or sometimes peripheral echogenic foci, which can mimic microcalcifications.
There's typically this classic boundary posterior hypoechoic zone that you may see.
And one of the hallmarks is that it might change.
If you don't catch this and you're worried that it's a thyroid lesion and you send it back for biopsy, if you look at the prior study when the patient comes for the biopsy, usually these lesions look quite different between two different studies.
Ideally, you'd make this diagnosis from some of the features, but here again is this boundary hypoechoic zone, and the posterior aspect of the thyroid gland.
In this case, I think this lesion does look extrathyroidal.
And what you wanna look for is areas of shadowing, which usually represent air in the diverticulum, and ideally you'll be able to see this connection to the esophagus.
Here's the esophagus posteriorly.
Here's a little shadowing from the air.
And this lesion was connecting up to the esophagus.
Again, usually these are left sided, but occasionally you'll see them on the right.

Other Differential Diagnoses

Our differential diagnosis for neck masses is again listed here.
I'll discuss more of these lesions, but I won't show you images at this time.
Central compartment lymph nodes, again, if the surgeon does a limited or incomplete central compartment nodal dissection, you can have residual central compartment nodes, both normal and abnormal.
In Hashimoto's disease in particular, the patients will often have markedly enlarged and hypoechoic nodes in the central compartment.
Regrowth or residual thyroid tissue can be a result of incomplete surgical resection of the thyroid or regrowth of thyroid tissue.
And we're seeing more and more cases of these because several patients with micro papillary cancers are not referred for radioactive iodine ablation.
And again, parathyroid glands can present in this way, but most patients will be symptomatic and have elevated calcium and or PTH.

Ultrasound of Cervical Lymph Nodes in Differentiated Thyroid Cancer

Now I'm gonna move on and talk about ultrasound of cervical lymph nodes in differentiated thyroid cancer.
Again, we've been discussing that ultrasound is accurate in the preoperative evaluation of lateral two through four, and also level five lymph nodes in patients with thyroid cancer.
And preoperative ultrasound is used to determine necessity and extent of nodal dissection.
The surgeons at our institution rely very heavily on these preoperative ultrasound assessments to tell them do they then need to go on and do a lateral nodal dissection in addition to their thyroidectomy CT is reported in the literature, have greater sensitivity in the central compartment than ultrasound.
Typically if I see an abnormal central compartment node, I'll report it to the surgeons, but they know that they need to decide at the time of the thyroidectomy if they need to go on and have the patient undergo a central node compartment dissection.
Macroscopic nodal mets are known to impact recurrence, and it's unclear in the literature if they actually affect survival, but certainly morbidity of recurrent disease and the need for additional surgery occurs if these nodes aren't removed at the time of initial surgery.
Again, in our institution, we do something called preoperative ultrasound mapping of the jugular chain lymph nodes prior to surgery.
And it's part of the published guidelines for newly diagnosed papillary thyroid cancer.
If there are any pathologic nodes determined at the time of the ultrasound in either the central or lateral compartment, they should be removed at the time of the initial surgery.
And remember that we're not looking for enlarged nodes, we're looking for morphologically abnormal nodes.
And here's a schematic of the lymph node compartments of the neck.
Level one and level two are outlined in this slide and level two through level four and including level five in this slide.
And then remember that level six is also called the central compartment, and it is the space between the carotids from the hyoid bone down to the suprasternal notch.

Normal Lymph Nodes

A few images of normal nodes, they're typically elliptical or elongated and oval shaped.
They have a flattened appearance in the sagittal plane and sometimes can look a little more rounded in the transverse plane.
Many of these will have a central echogenic hilum.
Here is a picture of a normal node that does not contain a hilum.
Simply absence of the hilum is not in and of itself pathologic if the node looks otherwise normal.

Abnormal Lymph Nodes: Features and Cases

I will talk to you again about ultrasound features of lymph node metastases and differentiated thyroid cancer.
Absence of the fatty hilum, and I'll describe a little bit more findings of this later.
Cystic change, calcification, rounded shape, abnormal color doppler pattern, hyperechoic changes and mass effect on the jugular vein have all been reported to be features of nodal metastases from differentiated thyroid cancer, both medullary and papillary cancer.
What we wanna do is look transversely along the jugular chain to detect adenopathy.
And remember, morphology and echogenicity of the node are much more important than size.
These lesions are less than a centimeter.
However, this lesion has a little bit of an irregular shape and contour.
This lesion is taller in the AP dimension and somewhat rounded in shape.
There are echogenic foci and little microcalcifications in here.
These nodes are suspicious for metastatic adenopathy.
Sometimes the nodes can retain their elongated shape, but have abnormal echogenic components.
This is a lot fatter and more lobulated than a typical fatty hilum.
Although sometimes older patients can have prominent fat in the hilum of their nodes.
These two nodes, again, they're elongated.
They do have mass effect on the jugular vein and multiple echogenic foci, including probably micro calcification in this case.
Again, another abnormal elongated node.
It's elongated, but it has this focal hyperechoic area within the node.
It doesn't look like a typical echogenic elongated fatty hilum.
We put a needle into this small two to three millimeter focus, and the FNA came back positive.
And we actually did not send the thyroglobulin because we had positive cytology.
Here's another case with one of these tiny echogenic foci.
We put a needle right into the lesion.
The cytology came back negative, so there were inadequate cells to make a cytologic diagnosis.
However, we always rinse the needle tip and store the saline specimen with the washing in the refrigerator and then send it off to the lab for thyroglobulin if the cytology comes back negative.
And in this case, the thyroid globulin specimen was positive and this was recurrent or metastatic papillary cancer to the nodes.
Here's another 50-year-old patient with papillary thyroid cancer on two year follow-up.
His elevated thyroid globulin had bumped.
He has this elongated node, however, it has tiny echogenic foci which represent microcalcifications.
And this was metastatic papillary thyroid cancer.
Again, more lesions that are suspicious for metastatic disease in the nodes.
Here's the jugular vein.
Here is this more rounded node with cystic components and calcification.
You can see shadowing from the calcification.
We actually biopsied this node went right through the jugular chain.
You have, right through the jugular vein.
You need to do short excursions here to get your specimen and then pull right out of the jugular so you don't lose your specimen with blood.
From the jugular vein coming into this, the needle again, here's this lesion with cystic change and microcalcifications, highly suspicious for papillary thyroid cancer.
Remember that the echogenicity of the metastatic neck nodes can be different from the primary.
Here's a patient whose primary lesion is markedly hypoechoic and it has macrocalcifications.
And she has this left supraclavicular or level four lymph node, which is actually echogenic, not hypoechoic.
And there are no calcifications.
And this was metastasis to the left level four jugular chain.
This patient had three months prior to coming to see us, had a biopsy by her endocrinologist and was not referred for preoperative ultrasound imaging of the nodes.
She went straight to surgery and then they noticed that her thyroglobulin did not go back to the normal range after the thyroidectomy.
And she had a whole host of abnormal nodes in her neck.
Here is an enlarged node with cystic change.
Here is a sort of tall rounded node.
Here is another node with echogenic areas and then a node with abnormal color flow and cystic change.
Here's a 38-year-old vocalist with a history of papillary cancer who was not motivated to have further surgery because he was worried about his recurrent laryngeal nerve.
However, his thyroglobulin was elevated.
He has the elongated node with partial hilum and then partial replacement of the node with these cystic changes.
Cystic changes of the node and also mass effect on the internal jugular vein in this case.
And again, same patient at the level of the scar.
He had this node with this large echogenic area.
An echogenic node in a patient with papillary cancer is suspicious.
And again, an elongated node with abnormal echogenicity and a focus of micro calcification.
Again, same patient, you can see portions of the hilum.
And then this echogenic focus at one pole of this elongated node.
Again, echogenic focus within an abnormal jugular chain node.
Abnormal nodes also contain disorganized peripheral color flow.
And you wanna try to, when you do these FNAs, you wanna try to direct the needle away from the vascular component.
It's pretty hard to do in this case 'cause there's a lot of hypervascularity.
Maybe you can draw a little fluid off the cystic component.
Here's an example of a case with an echogenic focus, which FNA pretty hard to get anywhere.
But this area which had color flow.
And you can see this node blew up to be twice the size from hemorrhage within the node.
And again, we've seen several cases while we were looking at other features of metastatic nodes, which have mass effect on the jugular vein.
Here's the carotid in the jugular being displaced posteriorly laterally by this node, which was very echogenic and also contained microcalcifications, again, elongated echogenic nodes with mass effect on the jugular vein.

Caveats and Pitfalls

I'm gonna leave you with this case of a hyperparathyroid malpractice attorney in whom we were looking for a parathyroid adenoma.
He had this hypoechoic mass posterior to the lower pole.
It was slightly atypical in that it was more echogenic than is typical for a parathyroid adenoma.
The nuclear medicine sestamibi study was actually positive on the opposite side.
And when I was reporting out this case, I noticed this small six millimeter lesion in the thyroid gland with a little echogenic focus.
Mentioned that it probably should be biopsied prior to his parathyroidectomy 'cause it has some features of papillary thyroid cancer.
The patient did not have the lesion biopsied, rather, he had a history that we were not given at the time of his parathyroid ultrasound of having had head and neck irradiation as a child.
The surgeon just talked him into having his parathyroid and his entire thyroid gland removed rather than biopsying the lesion.
Unfortunately, the patient did have a papillary thyroid cancer.
He was given radioactive iodine and his thyroid globulin was still elevated.
Two months post-op, he came back for a scan and we saw this irregular shaped node with hyperechoic areas, probably microcalcifications disorganized flow and mass effect on the jugular vein.
A patient with a six millimeter papillary thyroid cancer with a history of head and neck irradiation and already has jugular nodal metastases in that even though he had such a tiny lesion, we biopsied this and this was metastatic papillary cancer.
Just to show you that it's really important even in the patients with micro papillary cancers to look for those abnormal jugular chain nodes so they can have the proper surgery at the time.
They have their thyroidectomy.
Just a couple caveats or pitfalls of nodal metastases in differentiated thyroid cancer.
Just remember that the absence of the fatty hilum is actually reported to be the least accurate in predicting malignancy.
If you FNA lymph node and it comes back negative, if there's abnormal morphology, it could still be a metastases.
Sometimes you just are not able to get a good FNA specimen with accurate cytologic diagnosis.
If FNA of the node is negative, you can assess the thyroid globulin content of the nodes.
You can rinse the needle tip and saline, put it in the refrigerator and either send it right away or wait and see if the cytology is negative.
In terms of both Hashimoto's disease and the central compartment, remember that calcification and the abnormal doppler are really the only accurate predictors of metastases in the central compartment or level six.
A lot of times these nodes can be hypoechoic and more rounded appearance.
Calcification and abnormal doppler can be helpful.
A pitfall is in particular in Hashimoto's disease, in patients who have both Hashimoto's and papillary thyroid cancer.
Even the lateral compartment nodes and the central compartment nodes are often enlarged and rounded and hypoechoic and can mimic metastatic disease.
And in the literature they state that cysts and calcification are the accurate predictors of metastatic disease in Hashimoto's thyroiditis.
A study in 2003 in the surgery literature stated that abnormal lymph nodes that were unappreciated clinically were detected after ultrasound in 20% of cases.
Surgical management was altered in about 40% of cases, and this decreased cervical recurrence to 6%.
More and more you're gonna be asked to scan these patients preoperatively prior to their thyroidectomy to determine whether they have jugular chain metastases at the time of their initial surgery.

Other Cervical Lesions

Other cervical lesions that we can see when we're scanning the neck in this patient population include congenital cystic lesions.
We'll talk today about thyroglossal duct cysts, branchial clefts and lymphangioma or cystic hygroma.
We will not discuss some of the other cystic lesions of the neck.
And again, I'll just touch briefly on non nodal masses of the neck Infectious disease processes such as abscesses or scrofulous adenitis are better detected with CT or MRI rather than ultrasound.
Although in children, ultrasound is often the first line study that is ordered neurogenic tumors.
I'll show you a few examples.
I've encountered a few of these in my practice and mesenchymal tumors.
The example that I'll show you is of a lipoma.

Thyroglossal Duct Cysts

Thyroglossal duct cyst is a congenital anomaly that is related to the thyroglossal duct remnant, which extends from the base of the tongue into the suprasternal region.
Most of these lesions occur anywhere along the remnant, however, the majority of them are anatomically related to the hyoid bone.
It's important to describe these lesions as whether they're located inferior, superior or at the level of the hyoid bone.
The majority of these lesions are at or inferior to the hyoid bone with about 25% suprahyoid or above the level of the hyoid bone.
The role of ultrasound in the clinical diagnosis of thyroglossal duct cyst is actually to confirm the clinical diagnosis and to determine the relationship to the hyoid bone.
You want to also, since you have the patient in your lab, you wanna look for internal solid components that are suspicious for malignancy.
A very small percentage, about 1% of these patients can have papillary thyroid cancer within a thyroglossal duct cyst.
You also want are charged with detecting the presence of normal thyroid tissue in the neck.
Those are sort of your duties as a radiologist scanning the neck.
Here's an image of a thyroglossal duct cyst.
Often these lesions will have internal debris or proteinaceous fluid.
Again, there's posterior acoustic enhancement.
We know this is a cystic lesion if you put color on, should not see any color flow in there.
And again, your duty is to look down and make sure that this is not the patient's only thyroid tissue.
You wanna look down and make sure there is a normal thyroid gland in the region of the thyroid bed.
Another case here is the hyoid bone.
This lesion is at the level of the hyoid bone.
And again, this is a lesion which has internal echoes due to proteinaceous material.
And some people call this a pseudosolid appearance.
Here's a case which has thickening of the wall of the cystic structure and some septations and abnormal color flow in the adjacent soft tissues.
And clinically this was infected with hyperemia of the infected components.
And finally, I only have one case, but a case of a complex thyroglossal duct cyst, which had solid components and internal color flow.
I biopsied this lesion and the diagnosis was papillary thyroid cancer occurring in this thyroglossal duct mass, which was located in the midline right under the chin.

Branchial Cleft Cysts

I'll move on to talk about second branchial cleft cyst.
These represent 95% of all branchial cleft anomalies.
They occur in children and young adults, and they have a variable ultrasound appearance.
However, the anatomic location of these lesions is the clue to the diagnosis.
They're typically superficial to the common carotid artery and jugular vein and posterior to the submandibular gland, and they occur along the medial margin of the sternocleidomastoid muscles.
Location, location, location.
This is an elongated mass with this proteinaceous material.
It's cystic with no flow on power doppler.
It's located anterior to the common carotid and jugular vein and occurs along the medial margin of the sternocleidomastoid.
This is a second branchial cleft cyst.
And you may see these when you're scanning the thyroid gland in patients.

Cystic Hygromas (Lymphangiomas)

I'll go on to some more common neck masses that you'll typically see in the childhood population, cystic hygromas or lymphangiomas.
Most of these, again, will present in childhood, rarely you'll see them in young adults.
CT and MRI are often required to determine the full extent of these lesions and to map out the lesions prior to surgery.
They can be multiseptated with internal echoes.
And they typically are thin walled and you can easily compress them.
You may see hemorrhage into the lesions and if they have hemorrhage or infection, they can become thick walled and poorly defined and have internal debris within them.
This is a case of a 10 month old daughter of a pediatrician who had neck swelling and this complex cystic mass.
There was actually some color flow in these areas, which we thought may have represented thickened septations.
We gave a rather large differential diagnosis but wondered if it was an infected lymphangioma.
And this actually was aspirated and came back MRSA abscess, again, CT or MRI better in the clinical setting of infection.

Neurogenic Tumors

I'll discuss briefly neurogenic tumors.
I've seen several of these while I have been working at patients with history of prior thyroid malignancy.
They're typically hypoechoic and homogeneous.
They demonstrate posterior acoustic enhancement and often we'll have some intrinsic color flow with color doppler.
What you wanna look for to make this diagnosis is continuity with the peripheral nerve.
In this case, you can see this hypoechoic mass contiguous with this peripheral nerve.
And actually, one of the things that I have used as diagnostic, if I haven't prospectively thought of this lesion, is that when I've biopsied these lesions, the patients have had excruciating pain during the FNA.
And again, remember that you can't distinguish schwannoma from neurofibroma or any of these malignant neurogenic tumors.
You can't distinguish those with ultrasound.
Here's a patient who I was scanning who had a history of papillary thyroid cancer who had this rounded lymph node anterior to the jugular, which I was worried about a level four node.
I biopsied it.
I typically use lidocaine, so I infiltrate the lidocaine into the perilesional soft tissues.
The patient did fine with that, but every time I stuck the FNA needle into the lesion, he screamed out in excruciating pain.
I went back and looked at my images and I just in retrospect saw this little bit of peripheral nerve continuity.
And this turned out to be a peripheral nerve tumor.
Again, some images from the literature, this hypoechoic lesion, it does have posterior acoustic enhancement and you can see the continuity to the peripheral nerve.
Another lesion with peripheral nerve continuity.
Common sites include the vagus nerve, the brachial plexus, and the cervical sympathetic chain, and the ventral and dorsal cervical nerve roots.

Lipomas and Soft Tissue Masses

And again, I don't know if a lot of you out there are having the same syndrome that we are with a lot of these lesions every day that we are scanning that are palpable abnormalities.
Typically these are soft tissue masses.
I call these lumps and bumps.
Many of them occur in the neck.
Most common, these are cervical nodes.
And if you see some of the benign features, you can safely state that these look like cervical lymph nodes with no suspicious morphology.
We also are seeing soft tissue masses including lipomas.
And I always ask myself the question, can I be certain that a mass that is similar in echo texture to the surrounding fat is not a low grade liposarcoma.
Liposarcoma, I also read CT and I know that enhancement of soft tissue components is one of the diagnostic features of a low grade liposarcoma.
In the literature, I've looked up this topic frequently and most of the literature has statements such as ultrasound can support the clinical diagnosis of lipoma.
A lot of people use the correlate clinically disclaimer in their reports.
I sometimes think of this as punitive reporting.
Usually what I will say is ultrasound is non-specific in the evaluation of soft tissue masses.
And sometimes if I'm looking at a lipoma, I'll say, cannot distinguish a lipoma from a low grade liposarcoma.
Here are some of the articles in the literature which I have found.
Notice some of the titles, ultrasound and soft tissue mass lesions, a note of caution, ultrasound of soft tissue masses pitfalls in interpretation.
There's not a lot of compelling literature about our ability to diagnose these soft tissue lesions.
I will briefly then discuss the ultrasound features of lipomas.
They're typically subcutaneous or can be intramuscular.
About 15% of these will occur in the head and neck ultrasound typically demonstrates a well-defined typically avascular or at least hypovascular mass.
They're, you typically will see these linear echogenic streaks parallel to the transducer plane, and they can be variable in echogenicity depending on the fat versus water content and the number of interfaces with these little echogenic streaks.
Sometimes there'll be echogenic and sometimes there'll be hypoechoic.
In this case, the history was left neck mass present for 10 years, evaluate.
Clinically it sounds like they were suspecting something benign.
And imaging wise, it looks benign.
Based on imaging alone, can we be certain that we're not dealing with a malignancy?
Not really, but if you combine the imaging and the clinical scenario, unlikely to be a malignancy.

Ingrown Hair Example

And finally, I'll end with this case.
Scan the palpable.
It was a 29-year-old male with a palpable neck mass and he was actually referred for a thyroid ultrasound.
When the technologist scanned the palpable mass, she saw this little bit of a heterogeneous mass.
There were these echogenic lines within it.
She thought that there might have been some color flow and I asked her to go back and put a lot of gel and scan the superficial region.
Here is a little connection to the skin surface with this echogenic line confirming probably a clinical diagnosis in a young male with a small palpable superficial skin lesion of an ingrown hair.
Seems quite ridiculous that we're scanning things like ingrown hairs.
One of my colleagues would call this a radiology.
But this is again some of the things that are turning up in our ultrasound lab when we're charged with scanning these palpable abnormalities.

Summary

In summary, we have talked about cervical lymph nodes, both normal and abnormal.
In particular, the abnormal appearance in the patients with papillary and medullary thyroid cancer.
We've discussed masses in the postoperative bed in the same patient population.
We've also briefly discussed some congenital cystic lesions that you may see when you're scanning the thyroid patients.
And also briefly discuss some of the limitations of imaging the non nodal masses of the neck.
I will reference this article, which was quite good in radiographics in describing ultrasound of the major salivary glands.
If you're interested, hope I didn't put you to sleep with this lecture.
I showed you a few red herrings such as Zenker's diverticulum and cervical ectopic thymus which you might run into during your radiology careers.
And thank you very much for your time.