Ultrasound of the Hand and Wrist - HD

Ultrasound of the Hand and Wrist: Lumps and Bumps

In the next 30 minutes I'm gonna just cover ultrasound of the hand and wrist. And that largely implies we're gonna be talking a lot about lumps and bumps.

There are several different types of soft tissue lesions. I use the word lesions 'cause not all of these are tumors, but when patients present with something around their hand, their wrist, sometimes even on their forearm, ultrasound is a really good modality to sort this out.

We did a study a long time ago and looked at what experienced hand surgeons diagnosed a lump and bump as just simply solid versus cystic versus what ultrasound could do. And they were wrong 50% of the time, so you could have flipped a coin to make a decision. So ultrasound really does play an important role.

And what I'm also gonna try to impart is that as we go through and talk about all these different lesions, there are some clinical clues and physical examination clues that can really help you hone in on what it is if you think it's solid and perhaps the type of solid lesion that it is.

So there's several different kinds of lesions. We're not gonna have time to talk about all of them, but as you can see from this list, this includes both solid and cystic lesions.

Ganglia

The most common hand lesion that you're gonna run into is a ganglia. And these are mucin filled fibrous line cysts. They don't quite know what the etiology is, but it's often been purported that there's stress on a joint capsule or ligament that stimulates mucus production and leads to the formation of a ganglion.

And these can arise all over the body. They can arise from tendencies, ligaments, joints, or even bones. I recently saw a patient who had surgically proven ganglions on her tibia.

Depending on where they're located, often correlates with the symptoms they might have. Some patients might have very focal specific wrist pain that is amplified when they move their wrist.

One of the more common ganglions occurs on the dorsum of the wrist. And if there's irritation of the posterior interosseous nerve branch, which is a branch of the radial nerve, this can cause very focal pain. And oftentimes the patient will point to a very specific location, but there's nothing palpable. And this is known as an occult dorsal ganglion. And these are very, very tiny one to two millimeters. And if you were to just palpate that area with the wrist, you don't see it.

We did a study quite a while ago just looking at the characteristics of ganglions and why initially many were thought to be simple. We found out in our study that in fact many more were complex.

So when they're simple and some the simple ones tend to occur in certain locations, they're anechoic, they're avascular, they have an imperceptible thin wall and you don't see any color doppler flow.

But these can also be multiloculated. They can dissect around the wrist, they can have a thick wall, they can have debris, which is the mucin, and they may have color doppler flow, but this is really a rare finding.

They can also be solid appearing. And typically this happens when the ganglion has ruptured. And if you get a good history from the patient about the size of the lesion originally and that now it's gotten smaller, what you might think was a solid tumor may in fact just be a ruptured collapsed ganglion.

So here's a characteristic appearance of a dorsal ganglion. This is your scapholunate area. Your scapholunate ligament right in here. And then here's this anechoic thin walled ganglion. This is a transverse view.

And then when you turn on a sagittal view, here's your capitate bone. And here again you can see this ganglion and they're very easy to put on measurements. It's very helpful to the surgeons before they go in if they choose to remove these.

Here's one that was quite interesting. It's multiloculated, it's septated and it dissected all over the dorsum of the wrist. This is a little bit of the radius, this is the area of scapholunate. Here's capitate. And then you had all these locules. Here you can see one of the extensor.

So this would be a ganglion that would be far more difficult to remove.

Now there are other locations as well that are less common. One is on the volar aspect of the wrist and it's the volar radial side. And these can originate from either the capsule of the radioscaphoid joint capsule of the scaphotrapezial or even the flexor carpi radialis tendon sheath itself.

And typically these patients don't have any symptoms. They just know they have a bump on the volar side of their wrist, but if they were to bang it against something, it could certainly become painful.

So I'd been looking for years for a really pretty flexor carpi radialis tendon sheath ganglion. And it wasn't until recently that I saw this. This is a flexor carpi radialis tendon. And you can see within the tendon sheath there's this anechoic cystic area that's a intra tendon sheath ganglion.

These also can occur on the flexor side of the fingers. Patients will feel a little bump along their fingers and most typically they arise either at the level of the A one pulley, the metacarpophalangeal joint or the A two pulley, which is at the proximal phalanx level.

And these cysts, if you were to move your finger, they're tethered by the pulley. So you, whereas you can see the tendon itself moving, the cyst itself would not. And most of the time these patients are asymptomatic, but they, if they were to grab something and grip it with their hand, then they would feel pain.

And this is what these look like because of the small size of these, most of these tend to be simple in appearance. Here's your flexor tendon, this is at the level of the MCP joint. And you can see this little anechoic ganglion. You can beautifully see them in both planes, longitudinal and transverse.

Sometimes you incidentally discover them looking for something else and the patient isn't even aware they have this.

Giant Cell Tumor

Okay, let's move on to some other entities that you might see. One is a giant cell tumor. The name was changed by the World Health Organization, which seems to change names of lots of different things along the way. But this, they're now referred to as a tenosynovial giant cell tumor and they're the second most common hand lesion.

And they're benign. The cells resemble synovial cells and they arise from the tendon sheath itself. So likewise, they too. If the patient were to move their fingers and flex them, the giant cell tumor would not move.

Typically these slowly enlarge and they're non-tender and I've seen patients wait until virtually their entire finger from DIP up to MCP. It has just this sort of lobulated firm tumor growing up their finger, they tend to be on the volar surface.

So occasionally I've seen them on the dorsal side of the finger and usually they're hypoechoic homogeneous. They may show posterior acoustic enhancement. Their margins are well defined.

And the key that helps you sort out that this is not a cystic lesion is that there's internal vascularity. It's the easiest way to sort out solid versus cystic. And if these have been there long enough, they can also cause adjacent bony erosion.

So here's a giant cell tumor of the tendon sheath. You can see it's hypoechoic. It looks solid. There's some through transmission. And you can see it's caused some bony erosion. When we turn on color, clearly there's internal vascularity, which tells us right off that this is solid rather than cystic.

Here's another one that's rather lobulated as it's growing down the first digit, it's on the dorsal side of the thumb, but you can get a pretty good idea of how to measure this both in a longitudinal transverse plane. And when you turn on color, lots of internal flow.

So again, you know this is solid rather than cystic and you could often turn on it in a transverse view and also see the tendon, which helps you localize it to the tendon sheath. So that's a really key feature that helps you figure out that this is a giant cell tumor.

Hemangioma

Another fairly common tumor that we see is a hemangioma. And obviously these are benign. They account for about 10% of the hand tumors and typically they're capillary, which is more common in infancy or cavernous and in the hand they tend to be in the subcutaneous tissues.

And these two are slowly growing and painless like a giant cell. But one feature that would help you differentiate is if you take a close look at the area of the tumor, you see a little bluish discoloration of the skin. And I've seen that a few times, which has helped me with the diagnosis.

So again, looking at the location, turn on the lights in the room and feel it, move it around can really be helpful. These two are hypoechoic and solid people have talked about flow.

I've as many hemangiomas as I've seen over the years, I've never seen flow. When you feel them, they're sort of rubbery, a little bit compressible. They too have well-defined margins.

And if you were to turn on color doppler, they're hypervascular. And if you were to get a waveform, there's a lot of low resistance arterial flow and here's what they look like.

This is one on the fifth MCP joint. You see this hypoechoic lesion. You see these anechoic spaces and could sort of con you, you would think maybe this is where you would see blood vessels. And in fact when you do turn on color, those were vessels in that area.

So it gives you a pretty good idea that this is going to be a vascular tumor. Here's another one. This was in between the second and third digits and there was definitely bluish discoloration of the skin, which was very helpful 'cause otherwise, you have a nondescript lesion and it might be difficult to sort out a giant cell because I've seen giant cells be towards one side of the tendon and grow into the interspace as well.

And it could be confusing but you know, there are times you have to give a differential. But there are just little things about some of these lesions that can help you hone in and favor one diagnosis over another.

And as you can see, this is really a very hypervascular lesion.

Peripheral Nerve Sheath Tumors

Another lesion you might run into is a peripheral nerve sheath tumors. These may be schwannomas neurofibromas or malignant peripheral nerve sheath tumors. And these are usually in the setting of neurofibromatosis.

These can be benign or malignant. They're of a schwann cell origin and they too are slow growing and painless.

So what might help you to discern these is look for that entering and exiting nerve. So whenever you see a solid hypoechoic lesion, just look at the ends of the lesion. See if you can see an entering exiting nerve.

You also may see, and it's often hard with very small tumors, but schwannomas tend to be more extrinsic or sort of exophytic versus neurofibromas more central in their location in relation to the nerve. But this is very hard to sort out with small tumors.

Schwannomas also like to occur on the flexor surface of the forearm and hand. And I've seen a couple that have involved the ulnar nerve.

So on ultrasound, they too can be hypoechoic just like some of the other tumors we talked about. But they can also be heterogeneous. And you may see a target sign and your schwannoma can also undergo cystic degeneration. You may also see posterior acoustic enhancement.

And again, it's difficult to sort out the different tumors. But if you can show the entering exiting nerve, that can be very helpful and they too will show internal vascularity.

So here's an example recently on a nerve tumor, the radial nerve, this patient hasn't had surgery yet, but it's difficult to get both the entering, exiting nerve in the same plane. But we could see both. And this just shows the entering nerve here. And this too has some vascularity to it.

Lipomas

Lipomas are very common. I swear some days I see half a dozen all over the body. It just seems to be the most common lump and bump that we see.

I'm not sure why clinicians can't sort this out. Even when they're squishy and they've been there for 10 years and they're not growing, they still get an ultrasound. But at least it's quick, it's cheap and I don't think we're causing or costing the government too much money diagnosing all these hundreds of lipomas in the hand and wrist.

They tend to be subcutaneous, but they can also be intramuscular in the hand. Deep down in the palm. These tend to grow slowly. The patients sometimes aren't even sure they just discover them one day and they can't tell you how long they've been there.

But they too, sometimes they're very soft, sometimes they have a little more rubbery feel. They're very mobile. And what patients have sort of taught me over the years, especially in lipomas and other parts of the body, is that they can hurt, they can be tender and our surgeons will remove them if they're causing the patient's problem.

If they're deep down in the palmar space in the hand, they can compress the nerves in that case these would be surgically removed.

They tend to be more elongate. They may have a thin capsule, but sometimes they're so ill-defined. It's difficult to even put cursors on these and figure out where they begin and where they end.

And in other parts of the body, we often just describe this as asymmetric adipose tissue. 'cause you really can't measure it and you don't see a difference in the echogenicity of that area compared to other areas of the subcutaneous tissue.

But these can be hyperechoic iso or hypoechoic to subcutaneous tissue. And I think for the most part, most of them that I see are either slightly hyper or isoechoic.

And an important feature of these. So you don't confuse these with other lesions like a sebaceous cyst or something. As you often see these echogenic septations running through these lesions.

If a patient comes with a large one and says it's been rapidly growing, we worry about a well differentiated liposarcoma and these patients we would recommend an MR if there's a significant change. And this is really highly unusual. Most of the time in the hand and wrist. They're small little lesions.

Here's one that was in the thenar eminence. It seems to be a fairly commonplace, I've seen a few of these over the years and you can see this slightly hypoechoic lesion with these thin echogenic septations within it.

Here's just a transverse view. So this one was pretty well defined and we were able to easily measure it and report that to the clinician.

Nodular Fasciitis

Nodular fasciitis is something that's rather interesting. I've had a few patients over the years where we've put this in the differential and the case, I'll show you, we were able to get pathologic proof, but it is a benign soft tissue tumor.

And they're composed of fibroblastic myofibroblastic cells with a fibromyxoid matrix. And typically they're located on the volar aspect of the forearm, which is where I've seen about three of these.

They're rather rare in the hand itself and they can be in the subcutaneous tissues within the muscle or adjacent to muscle or in that deeper fascial plane adjacent to muscle.

And the typical history that you get, and this is a history I got in one patient that actually worked at the hospital and she said this came up very fast and has been rapidly growing and it had been there about three weeks. And they also complain of tenderness and pain. And particularly when you're scanning and compressing, they really complain.

And so this is a rather helpful feature is finding out how long it's been there, how quickly it's growing and whether or not it's painful.

So on ultrasound, these are well-defined. They can be lobular as they get larger. The ones I've seen were just well circumscribed. They too are hypoechoic. They can be heterogeneous. There may also be posterior acoustic enhancement and they definitely show color doppler flow.

And if you see it and they're attached to the deeper fascia, the location might also be helpful in honing in on this differential or on this diagnosis.

The differential itself includes sarcoma. There really aren't very many articles in the literature on this, but I'm gonna add a differential when I show you a couple of cases here.

So this is a patient with nodular fasciitis. This is just a sort of nondescript rounded, well-defined hypoechoic lesion with some through transmission on the volar surface of the forearm. But she's the gal who gave the, it's been there three weeks. It's rapidly growing and it hurts. And as you can see there's lots of color doppler flow.

So when I saw this and got the pathology, this patient came along not too much later and had this lesion on the dorsum of their thumb and also said, this is rapidly growing and it hurts. And I'm like, ha, I can make the diagnosis of nodular fasciitis again. And even the color Doppler flow pattern looks very similar to what we just saw.

But as you can see from the title of this slide, this wound up being a capillary hemangioma. So I guess patients and lesions don't read the textbooks, so be aware there may be other diagnoses as well. You know, we certainly don't want a patient to wind up with a sarcoma, but you do have to consider that. And now I throw capillary hemangiomas in my differential, but mention that typically these don't rapidly grow or hurt, although this patient's did.

Tenosynovitis

Okay, let's move on to tenosynovitis for a few minutes. Tenosynovitis is an inflammation of the synovial lining. Oftentimes it's idiopathic, but it may be due to inflammatory arthritis such as rheumatoid arthritis, crystal and tendinopathy, gout, CPPD and deposition diseases such as amyloid or infection, which is rare.

And I've only seen one patient with an infected tenosynovitis and that needs a hand consult right off the bat.

So what do you look for? Well, in general, you look for an effusion in the tendon sheath or debris. You look for synovial hypertrophy. If that hypertrophied synovium shows color doppler flow, then it becomes synovitis.

You look for bony erosions crystal and deposition in the joints, the soft tissue, cartilage, tendons, ligaments, and also some of these diseases can predispose to tendonitis and even tendon rupture.

This is an example of idiopathic tenosynovitis. For whatever reasons I seem to see it a lot in extensor compartment four, which is the compartment for your extensor digitorum tendons. And you can see this, it's very thick. And when we turn on color doppler flow, we can see there's definitely increased color doppler flow within this hypertrophied synovium.

Here's another patient where you have a bit of an effusion and then you have this nodular synovial hypertrophy. And again, when you turn on color doppler, lots of increased flow and sometimes these just come as a palpable bump on the back of the hand. And the thought is a ganglion.

A lot of patients are tender, which sort of steers me away when I see a focal bump and they say, this really hurts. I tend to think about a tenosynovitis as well.

Rheumatoid Arthritis

All right, we've seen, we're seeing more and more patients with rheumatoid arthritis or also a lot of patients who have hand and wrist pain and swelling, but all their workup is negative today thinking about more of a seronegative arthritis. But we're seeing more and more patients, in fact, we're booked out by a month trying to fit these patients into our schedules.

Rheumatoid arthritis is one of the more common diseases you'll see. It's an autoimmune disease, more common in women than men, usually in the age range of 35 to 65.

What you have is a proliferative synovitis that causes bony erosions, cartilage damage and joint destruction tends to have a proximal distribution. It's usually bilateral and it's also symmetric.

I find it very difficult if I don't have clinical information, which we usually do about the patient's history, the clinician's physical exam, what their laboratories show, and hopefully hand radiographs as well. I think all of that is really important to be able to make an appropriate diagnosis.

So we tend to see these patients where the question is, are there early inflammatory changes or patients who have known active synovitis versus having inactive disease? And the question is, the patient already has the diagnosis of rheumatoid arthritis, they're on medication for it, but they're just not responding. They still hurt.

So if we were to show active inflammation that is synovitis, then the clinician might consider a change in drug therapy, put them on biologics. Also, when we see active synovitis, it predicts relapse and radiographic progression, meaning increasing bony erosions because now you have that inflamed synovium.

Rarely we've been asked to monitor disease activity. I think most of the time that's done clinically.

So what we typically do is we look at the radiocarpal, otherwise known as the proximal joint space. We look at the mid carpal area, we look at the radioulnar joint, the ulnar styloid, the second and third MCP and PIP joints. This is where you tend to see disease. And also we look at extensor compartments four and six sometimes changes in the ulnar styloid, either an erosion or ECU tenosynovitis can be early findings.

And once you've done this enough you can usually get through this in a fairly organized and rapid manner.

So again, we look for thickening of the synovium. It's typically hypoechoic. We look for synovitis. So once I find a hypoechoic synovium, I turn on color doppler and this suggests active inflammation.

We look for associated joint effusions. You can often push on the joint to help you show that is an effusion. We look for bony erosions and I think we're nowhere near as good as what the rheumatologists think we are because we can't see all the way around on the radial and ulnar sides of the MCP joints in the wrist. And I think that's where having radiographs is very helpful.

John Jacobson published a nice article reporting a fairly high false positive false negative rate because of how difficult it can be in the rheumatology literature. They usually say two millimeter erosion in two planes you can make the diagnosis.

And then we also look for tenosynovitis and the extensor flexor compartments. And largely it's on the extensor side. If the patient doesn't have pain on the flexor side, I usually don't look there.

But I did have one interesting patient whose presentation was a flexor tenosynovitis. And then obviously if the patient's not moving their fingers well or there's weakness, then we investigate for tendon rupture.

So here's a sort of a classic example of a patient who had rheumatoid arthritis. You can see this hypoechoic thickening in the proximal compartment. This is capitate. That typical dip is a giveaway for trying to anatomically find that bone and it's just sort of peripheral to the scapholunate joint.

And then again, you see this very thickened synovium and when you turn on color doppler, you can see there's lots of increased flow. So this is active inflammation synovitis, you can also see it in the fingers.

Here's again some synovial hypertrophy. This is a second MCP joint and again, increased color doppler flow. Remember the tendon sheaths do not come down on the extensor tendons all the way down to the MCP. So you're looking deep in the joint deep to the tendons.

And I often find moving the fingers, moving the wrist can be very helpful in sorting all of this out. I also like the transverse view. This very nicely shows me the extensor tendon and here's all this thickening of the lining on the radial and the ulnar side and then just a little bit of fluid there and I just use lots of gel and keep the fingers together. And you can often see this very well.

Here's a patient probably the most exuberant synovial hypertrophy that I've seen at the radioulnar joint. This is the ulna, this is the radius. And you can see all this thickening of the lining.

This is a sagittal view over the radius. Again, lots of thickening, easy to turn on color doppler flow. This is the extensor carpi ulnaris tendon, the tendon sitting here. You see all this synovial hypertrophy and turn on color. There's lots of increased flow.

So this is tenosynovitis, erosions. This is gigantic. This one's not too hard to make the diagnosis. This is a second metacarpal head and they tend to be on the metacarpal side rather than the phalangeal side.

Here's another one you can nicely see on a transverse view. And oftentimes you'll even see color doppler flow going into this 'cause it's a synovium, the inflamed synovium that's causing this.

Here's another erosion of the third metacarpal head. You can see this is pretty ugly. You normally have this little dip here, so you don't wanna confuse that as an erosion, but this one is pretty obvious with all this synovium.

Tendon Injuries

All right, we're gonna finish up talking a little bit about tendon injuries. We tend to see two different kinds. One is avulsion of a tendon and often this is at the level of the DIP joint.

And what happens is kids are out playing, running around, somebody grabs somebody's shirt and all of a sudden the other person runs away and you have forced extension of the digit when the profundus muscle is contracted leading to avulsion of the flexor digitorum profundus.

And a lot of these patients come in and they can't flex their DIP joint. And unfortunately a lot of the primary care physicians don't recognize this. And the patient goes in, sees our doc, and he says, oh, you'll get better. You'll get your range of motion back and they never do.

And then finally they end up seeing a hand surgeon and they've avulsed the tendon and clearly the sooner you get these patients to surgery, the better they're gonna do.

The other thing we see probably more of is flexor tendon lacerations. Whatever you're doing with a knife or some kind of equipment in your job, we've seen this fairly commonly with avulsion.

You the tendon is no longer in the sheath and I usually like to start distal at the tip of the finger and then just scan proximally and longitudinal and transverse planes and usually you can find it how far it's retracted. And that's very helpful to the hand surgeon before they go in to know what they're dealing with.

Lacerations, you typically see a hypoechoic defect within the tendon at the site of trauma and it's helpful to the surgeons to measure the distance between the lacerated tendon ends.

So here's a flexor digitorum profundus rupture. You can see the tendon is back here. This is the fourth digit and it's back over the proximal phalanx, which is sitting here. So we could let them know exactly where it was.

Here's a patient who had a tendon laceration and it included both a flexor digitorum superficialis and profundus. This was the distance between the torn tendon ends of the superficialis, which you can see here. And then there's just this hypoechoic gap.

And this was a particularly pretty picture I thought, where you could just see the laceration right through the tendon, but it hadn't retracted quite as far as the superficialis.

Foreign Bodies

Another thing we're good at is looking for foreign bodies. People have accidents, things penetrate into their fingers. If it's radiopaque you can see it with a radiograph and that includes glass, metal and stone.

But if they're tiny, tiny little fragments, you're not gonna see it on a radiograph. And then wood is radiolucent. So that's where ultrasound can be very helpful.

Sonography articles written a long time ago have a very high sensitivity and specificity for finding these little areas and you wanna use lots of gel on the finger and then keep your transducer perpendicular to the long axis of the foreign body to try to see it on glass and metal.

You may get tiny little comet tail artifacts to help you out. And with wood you see usually an hyperechoic focus with some posterior shadowing and with wood, if it's been in there for a while, it starts to absorb water and it changes its appearance. And if it's a tiny little splinter, you may have a harder time seeing it.

So here's a couple of teeny teeny little glass foreign bodies. They measured about a millimeter and there's just no way the hand surgeon could go in there and even find these tiny little things. Here it is on a long view.

This is somebody who was a lab worker at the hospital and broke some glass and got embedded in the finger and went to the ER and they just sewed her up. But when she moved her tendons, she could feel these tiny, like something was inside and she was right.

This was an interesting case. I don't know why this person decided to embed a toothpick in the palm of their hand, but they did. You can see it goes from here all the way over to here. And fortunately they missed all their vascular structures, their tendons and nerves. So it was just sort of embedded there.

Ultrasound is also good for looking for complications, including abscess, where these foreign bodies might be, or depending on how long the patient waits to see someone, if they develop a soft tissue sinus tract or osteomyelitis or even if it's in the tendon sheath, the tenosynovitis.

If they're close to an artery, they could develop a pseudoaneurysm or they could have direct damage to the nerve if they pierce it.

Here is a patient who had a splinter that been embedded for a couple of weeks and you see this real hypoechoic area with these little echoes. And when we turned on color doppler, these areas didn't fill in and we could push and blot this area and see these little echoes moving around. And this was an abscess.

Conclusion

So as you can see, ultrasound really is an excellent test to evaluate little lumps and bumps in the hand and wrist in patient history. The shape of the lesion, the location, any signs and symptoms, and the ultrasound findings. If you pull all this together, it can really help you to provide an accurate diagnosis.

Thank you.