Ultrasound of Lumps and Bumps - HD

Goals in Evaluating Lumps and Bumps

I think when you sort of just think about lumps and bumps generally, and you say, okay, what's my end goal in this?

And at the end goal is actually to identify potentially aggressive neoplasm.

And then what's the second goal? The second goal is that if we can't potentially pick up the benign lesions by an ultrasound, since ultrasound is going to be our first sort of triage instrument is to minimize further imaging or potentially even further invasive procedures.

So I think if you keep those two goals in mind, you realize it's not so much about really coming down with a precise diagnosis, but it's a lot to do with trying to find out if it's something left alone, it's benign, or is it something which needs to be further imaged and biopsied.

Ultrasound Advantages and Practice Considerations

I won't go through the details on ultrasound. Its advantages. This is a very highly skilled ultrasound room.

Now, unfortunately when you do a gram ultrasound exam, there is really no getting away from the history and potentially, if possible, a physical exam.

Now, the way we practice here, it's a little bit different because the sonographer already does the exam and so many times you're remotely reporting and you don't have access to a physical exam.

And so we've trained our sonographers to at least in the jot pad, in the notepad, put in information about what it looked like.

So you the history you can pick up from the notes, but in terms of physical exam, you need some guidance on what was the firmness, what was the mobility of that lesion, was it tender during the exam? Was there any skin changes? Was there a color change on the skin?

Because all this will help you synthesize that information and put it into the impression.

Key History Elements

In terms of history, it's really important to know, is it a single lesion? Are there multiple lesions?

How long has this bump been there? Is it like a short time or is it a long time interval?

What's the rate of growth? If the patient says, oh, this has suddenly grown significantly, versus, oh, it's not grown for last three years, that helps us to quickly reach the point of making a diagnosis.

Is there any history of prior trauma? We saw some excellent images of intramuscular hematoma and Sharifi also talked about how it looked like a muscular hematoma, but turned out to be a sarcoma.

All those issues are there, is there history of trauma or not?

Any infection, ongoing infection to think about abscess and things like that in the history of anticoagulation, and things like that.

And is there a known malignancy? Because sometimes, and many times these bumps or lumps could just be metastatic disease, and the ultrasound appearance may be very nonspecific, but now your suspicion is much higher.

And even if you're thinking this looks benign, your suspicion is higher. So you might make a diagnosis of malignancy.

Technical Aspects of Ultrasound Imaging

Very important to choose the right transducer because the transducers now are really high frequency, up to 18 megahertz even higher, and the resolution is impeccable.

So sometimes sonographers have a tendency of sticking to a nine megahertz, 11 megahertz linear, and they do use that for everything, even though they have the ability to pick up the high frequency small transducer, which is available, and then optimizing the doppler.

And using extended field of view, sometimes you want a relationship, how far is the joint from this bump or how far is this tendon from this bump? And you need some extended field of view or a video clip so that you can make a good judgment.

Light touches, again, important because you don't want to press hard and kill the vascularity, which might be extremely subtle.

Ultrasound Descriptors for a Lump

Now, what are the ultrasound descriptors for a lump? You see a lump.

And in your report, what are some very important specific points you must say so that the orthopedic surgeon or whoever sent you the case understands exactly where that lesion is.

So you need to say, where exactly is it located in terms of anatomy?

What's its relationship to the fascia? Is it in it, is it above it? Is it below it?

What's the relationship to the vessels or nerves, especially the named vessels and nerves which are in proximity? Is it related to them?

You have to also comment on its connection with a joint potentially or no connections with the joint.

And then of course, size in terms of morphology, you use your gray scale and color doppler to comment on whether it's cystic solid, is it mixed? What's the shape borders?

Basically simulating your physical exam impressions into your ultrasound impression.

Benign and Malignant Lesions

Now, there is a huge list of benign lesions, which present as bumps and lumps.

And actually, if you ask me as a radiologist and as a clinician, and even as a patient, it is fantastic when you diagnose these because patient comes really concerned of this bump and you say, oh, I'm a hundred percent sure this is a sebaceous cyst, and he's happy and you're happy and your diagnosis is done.

And I think in the perfect world, I think that's how medicine should be practiced. You're not giving bad news to anybody else, but that's not the case.

But going through this list, we have these cyst bursa ganglion all day in and out to see them. Lipomas, vascular malformations, foreign body grans, superficial fibromatosis, muscle hernias and peripheral nerve sheath tumors.

A lot of this benign list of lesions.

And then in terms of malignant, it's a short list. It is a non-specific list. It is very intervention, biopsy based diagnosis of lymphoma, or do you have some soft tissue sarcomas or potentially a metastatic lesion.

Follow-Up Guidelines

As a couple of speakers alluded, there are no very set follow up guidelines on these lumps and bumps.

And sometimes it's sort of a gestalt, if you see a post-traumatic hema, I'm pretty sure there was trauma. It's a different thing, but sometimes you don't know if trauma got the patient to the hospital, but what you are thinking is a hematoma was a preexisting situation, and it's bleeding because it's a malignancy.

So you have to sort of come up with a little bit of a geal. If anything doesn't feel very right. There is really no harm in calling the patient back in two to three, three to six months and look for temporal evolution of that lesion.

This is really the most harmless way to quickly see if there's anything that changes in a short period of time.

Ultrasound Patterns and Anatomical Layers

So in terms of ultrasound pattern and it's critical to identify the layers and I think it's really critical to train the sonographers on identifying these layers.

The skin is generally echogenic. You can see on this image there's a little bit of a gel on the top just to differentiate that dermis layer from everything else and to create an acoustic window.

Then below that you have the subcutaneous fat, which is somewhat slightly hypoechoic, extremely variable in thickness.

And then you have the muscles which have these medium level echoes. This is a transverse image and a longitudinal image. It's more of a laminar pattern.

And then the fascia, the intervening fascia is hyper coic and maintains its appearance all through, the resolution has really reached the point where you can see these fascia extremely well.

Anatomical Examples and Dynamic Maneuvers

So taking an example of the abdominal wall itself, to understand a little bit of the anatomy, you quickly look at the understanding, okay, if this is the skin and if this is the subacute fat, then in the abdominal wall, this is the rectus muscle.

Then you have these three muscles on the side. You have the similar linear layer here, the external oblique, internal oblique, and transverse.

The other thing, and even if there is a lesion in any one of these layers, is to simulate a dynamic maneuver. What happens when the patient does something?

So in this instance, the patient contracts the abdominal wall, and you can see that the internal oblique sort of just becomes much more visible and brown in its appearance.

And all these little maneuvers help you understand what the layers are.

This is a midline, transverse image showing the two rectus muscles in the abdominal wall. And this is the linear alba right in the middle.

And this layer just below that many times is mistaken for some sort of a lipoma or tumor, but just prop peritoneal fat.

And here again is the more lateral line, which is between the oblique muscles and the rectus, which is the linear similar nerves.

Here's a little video to show you how in contraction in live, you can see these and if you wanna diagnose a hernia, you wanna diagnose any sort of muscle hernia itself, or a hernia coming from the peritoneal cavity. It's really important to get those maneuvers right.

This is a groin hernia here, very obviously there is a break there, and you can see herniation of the mostly fatty contents and no bowel in there.

So even though you might have a very clear bump gram image, I think it's really important to have some video clips in terms of dynamic maneuvers, which were done to illustrate what are the relationships of the anatomy when you are trying to decide where exactly a certain lesion is located.

So continuing with the relationship of layers, if you look at this layer, this is in the lower abdominal wall, and palpable lesion.

So you know that this is the skin, the substitute fat, and then you have the fascia. So this lesion is obviously very well located within the muscle itself, and you can see the peritoneal layer at the bottom comparing that with this lesion.

You can see, again, it's a bump gram. You have the skin, you have the subcu fat, you're down to the muscle. This is a lesion in the muscle, but if you look very carefully at the bottom, it is actually going through the peritoneum into the intraperitoneal component also.

So it's very important to define where exactly the lesion is and what is its relationship with the fascia around it, because it completely changes your approach based on its local infiltrative pattern.

This is a case from Sharifi from my work at Mallinckrodt, and this is a beautiful case of muscle hernia. There's a interrupted fascia over there, and you can see patient has to contract, and only then you will see it.

And that's the other thing in many of these bump grams, they may not be visible when patient's lying supine in the examination room. You have to simulate the maneuver that makes that bump really obvious.

Epidermal Inclusion Cysts

Now, this is the commonest thing. You see a lot of these epidermal inclusion cysts, and in a perfect world, this is how you would see it. You'll see a very well defined, you'll see a very nice antiqua cystic cavity, which is having a track that leads up to the skin.

Now this track is there many times, but if you increase the transducer pressure a little bit, then it sort of disappears. So it's critical to sort of find that track and then you know your diagnosis is done.

Also, look behind the lesion. A cyst has extreme through transmission over there. So it tells you that's a cystic lesion.

Now, when you do high resolution ultrasound, you can really have very good understanding of the dermal attachment in a epidermoid, in a cyst, in a sebaceous cyst.

And so it's important to use that and see what's happening. There's this study which talked about a clear delineation of the dermal attachment, and then there is this little focal dermal protrusion.

Even if the track is not there to clearly say that this is most likely a sebaceous cyst.

Now, when you put color doppler, the sonographers are very tempted to pick up these little vascularity in there, which is nothing but the debris and the junk and the cholesterol pistols.

They will give little twinkle artifacts. If you put a spectral doppler on that, it's not gonna translate to any important signal.

But on the color doppler, these little things will sometimes make you think that this is real color in this vessel, which is not the case. So be careful of that pitfall.

Here's a sebaceous cyst with ruptured. Once they ruptured, they're a little bit more difficult. Patient comes with painful symptoms, and this cyst has ruptured.

Here you can see some a track also moving up to the through the skin. Now, the track may not be absolutely well aligned because once it ruptures gets really oblique, so it's kind of important to sort of scan through and find the track itself.

There might be some focal inflammation around a ruptured cyst, so you can see a heterogeneous hyper quick appearance of the fat surrounding the cyst.

Fat Necrosis

Now in this case, you can see that this lesion is located under the skin in this acute fat above the muscle fascia, very well defined, but doesn't show really good through transmission.

And at the same time, you can't see any obvious track, at least not in these two images, which I'm showing you. So that relationship of layers becomes really important.

This is a case of fat necrosis, as was this case of fat necrosis. Fat necrosis is a very difficult diagnosis unless you sort of correlate with the symptoms.

Patients having, most of the time they are somewhat tender, but in terms of echogenicity, they can vary from being hypoechoic to hypoechoic or extremely heterogeneous.

In this instance, we had the benefit of the ct, but on ultrasound it was somewhat atypical appearance with sort of a fluid level over there.

But generally this is more likely fat necrosis, which you see corresponding to patient's area of pain. And there is this little heterogeneous area, small hypoechoic areas within it.

In this case, this is a much bigger portion of fat necrosis. You can see very modeled fat with a lot of diffuse shadowing.

Sometimes you can pick up a little bit increased vascularity, but you can see there's a lot of variation and that's why the clinical background becomes really important before making the diagnosis.

And if you are in doubt, just ask for a follow up, see what happens in three weeks. And if the patient is appropriately treated, the pain goes down and the fat necrosis sort of blends more with the fat itself.

Here's another case of fat necrosis. Seemed like a mass on the MRI did the ultrasound and looked like that heterogeneous area with small hypo coic in the middle.

This was biopsied and even the pathologist came up with fat necrosis side.

Lipomas

Continuing with the relationship with layers, we see tons of lipomas most of the time, sub acute plane or sometimes in intramuscular planes. Also, again, great demonstration that this is located within the sub acute fat itself.

The problem happens when you have a very large lipoma. I think once you go about five centimeters, it's really difficult for ultrasound to really conclusively say this is completely benign because there can be eccentric areas which either you're not seeing or you are not comprehensively evaluating.

So once they're barely large, it almost makes sense sometimes to get a baseline. MRI exam.

In this lipoma, there was some heterogeneous area eccentrically placed here. There's another eccentrically atypical sort of place there. There's another one fairly large.

And you can realize that we are limited a lot. There's a lot of attenuation taking place. So it limits the proper evaluation of this lipoma.

So then that lipoma in a well differentiated lipo sarcoma is the key, like are you gonna miss a well differentiated lipo sarcoma?

And there's this paper from Radiographics from 2005, which has couple of hints, which might help one that almost 50% of these lipo sarcomas are lesions that occur in the lower extremity, particularly in the thigh.

So if you sort of come across this sort of a large lesion and it is in that location, you would be more suspicious than, for example, elsewhere.

And then almost one third of these lesions are actually in the retroperitoneum, which happens to be the second most common location.

Now, this is not the patient who's gonna present with a bump gram, but that is the second most location.

So once you are gone beyond the proximal thigh area and the retroperitonium, then you have the other areas where you might find in head or neck.

So the further you go away from the retroperitonium and the proximal lower extremity, the lesser is the chance that you might be dealing with a well differentiated lipos sarma.

Having said that, the fact that if the lesion's big enough and you feel you have not fully conclusively evaluated, I do think an mr as a baseline is recommended.

Here's another case. This was sort of in the thigh and encroaching into the pelvis. We could see some vascularity. We could see an eccentric heterogeneous hypoechoic area.

This did biopsy was performed this area, and this did come out as lipos sarcoma.

Relationship to Adjoining Structures

Continuing with the relationship to adjoining structures, you look for a relationship to tendons. You look for relationship to nerves.

In this instance, there was this bump very closely associated with one of the tendons in the foot. And when you do dynamic maneuver of the tendon, the tendon was moving back and forth, but the lesion itself was not moving.

That almost implied that this was in the sheath itself. And on biopsy was one of the giant cell tumors of the tendon sheath.

Continuing with the relationship to adjoining structures, this was a very interesting irregularly marginated lesion around the radial artery.

I actually thought this must be lymphoma, the way it was sort of encasing it, but not really infiltrating the artery itself.

But again, once you start dealing with lesions which are having a very non-specific appearance, they're not fitting in any compartment. You know, the next step is going to be a biopsy.

The r also showed an enhancing lesion. So we underwent a biopsy, and when I was a little bit surprised, it did come as nodular fasciitis on the pathology.

Peripheral Nerve Sheath Tumors

The neuromas, you know, this is a Morton's neuroma between the interdigital web space in the foot. And if you really try hard, you can sometimes find an entering and an exiting vessel.

It's not as easy as it seems when you read in textbooks, requires a lot of maneuvers, and sometimes pressure between the inter digital web space from the planter aspect or from the top to try and make it visible.

Most of the peripheral nerve sheet tumors will be hypoechoic. They will show some sort of a through transmission, and because they show that through transmission they can be mistaken for a cyst.

Blood flow is a little bit difficult to demonstrate unless you are able to have a very light touch and set up the parameters very well.

But I think the key is to looking for a peripheral nerve continuity and your anatomy that is that the expected location for one of the known peripheral nerves.

Here's a couple of examples. At least in this one, you could see that there's a nice entering nerve, a little bit of a peak on the cephalic portion and a little bit of a peak in the caral portion, telling you an entering nerve and an exiting nerve, which would be seen with a neuro, with a neuroma.

Non-Specific and Malignant Lesions

So then once you are gone with these benign lesions and you've finished your understanding of its relationship with the nearby anatomy, you are left with multiple sorts of non-specific lesions, which invariably will end up being diagnosed based on a biopsy.

These could be metastatic or malignant lesions. So few examples about that.

Here's a lesion very clearly within the muscle. Here you can see that skin, that's a good fat. This is a muscle, it's very heterogeneous hair, but on dopplar you can see intense vascularity.

It's very irregularly lobulated. And this turned out to be a metastatic lesion.

Now hair's another case in which you have a hypoechoic mass in the region of the hip. And interestingly, initially we thought that this might be a cyst or a chronic hematoma.

This is the skin that's the subcu fat, this is the muscle. But on color doppler, the tech was able to convincingly show arterial flow within this hypoechoic lesion.

So this was obviously lymphoma on biopsy. So unless you use all the tools available for you, it can really masquerade as a benign lesion.

As another large diffuse B-cell lymphoma, fairly large encasing the vessel, then obviously biopsied on ultrasound, desmoid type fibromatosis is the other one.

Seen a few of those a little bit more frequently than we should sort of locally invasive lesion. And again, mostly diagnosed by doing a biopsy.

Now, here was an interesting lesion. This was a mass overlying the patella. And initially we looked at the underlying tendon and the tendon was not involved, which was interesting.

We did the maneuvers and was moving really well. This is the intra patella tendon here on the transverse plane, and there was a very good cleavage between the lesion itself and the patella tendon.

So obviously it was not originally from that I thought maybe some kind of bursa. But nevertheless, we went ahead and biopsied this, this is the mr characteristics of this lesion, and it can turn out to be a basiloid epithelial neoplasm.

So that does tell you that once you are dealing with lesions which are not falling in very typical pattern, you are going to end up doing a biopsy to make a more specific diagnosis.

Some more cases. This was a ilio region mass, actually. We came to look for the i for the hip area. And then by the time you sort of kept tracing this big mixers lesion, it did turn out to be a mix mite was actually encroaching along the ilio as all the way up into the pelvis itself.

And this was also biopsied and this was somewhat of a hard biopsy. There's a lot of cystic areas in these muco lesions. This tells you the extent of this lesion.

Okay, another case, this also was anterior hip mass. And initially I thought this is just a fluid collection in the bursal space, but this patient, this does not change over a period of time.

So we ended up biopsying this and this also did turn out to be a mix.

So I think that adage is true that with a lot of these masses, if they are not going to follow into a characteristic pattern and you follow them in three months or three weeks and you don't see any change, then it's better to actually put a needle and come to know what exactly is going on with these patients.

There's one more example of a mi. This was a little bit more suspicious just because it had this solid area eccentrically placed over there with a lot of vascularity in it.

Okay, here's a patient with, again, very irregular mass on in the forearm itself, large amount of vascularity seen within it and was biopsied. This was a poor carcinoma.

So you can see where I'm going with this that they have all these different types type of appearances, but there's nothing in ultrasound that is going to help you make a strong diagnosis one way or the other.

So I think limiting ourselves to knowing, okay, this lesion is looking super benign, I'm not gonna worry about it. And then once you are in the zone of indeterminate, I think you have to start thinking of myop, seeing these lumps and bumps.

Foreign Body Granulomas

Okay, I'm gonna show this just for completion many times. And we live in Arizona, so we have a lot of cactuses around us.

So you see this many times, people come up with it, a foreign body gran with some sort of void inside, and there's a inflammatory reaction around the lesion.

This is a patient who's underwent some sort of surgery, again, comes with a bump. And this was related to the suture itself.

You could see some of those sutures on the CT scan. And this is an inflammatory sort of collection all around it, suture granuloma.

Conclusion

So in conclusion, I think soft tissue masses have a very non-specific ultrasound appearance.

High frequency transducers do help us to get the echo pattern better, but I think the real clue is hidden either in the location or in the clinical history is really, really important to go into the history and see the physical appearance of these lesions.

Ultrasound will remain a first line modality before some other imaging is done in a lot of these bone programs. So you'll keep seeing a lot of these.

Knowing the caveats that when you need to do further imaging is really important and not try to be a superstar of trying to make a very histopathological diagnosis on every bump program.

Thank you very much.