UPDATED 10/10. LYMPHOMA on tendon - 8" above the hock. Experiences?

[endlessclimb]

My lovely, psycho, lovely mare has been persistently lame on the right hind for several months. Tried various injections (a la shotgun), nothing worked. This isn’t my first rodeo with mystery lameness, so… Bone scan time.

Everything looked normal (3/4 body, withers back), but… Of all things to light up “hotter than fire” (vets words), it is a distention about 8" above her hock on the large tendon that runs along the back of the leg (is that still the DDFT there? I’m not an anatomy expert). We are stumped because a) that lump has been there for awhile, and was dismissed as a windpuff type distention and b) why did that show up on the bone phase of the scan, not the soft tissue phase?

At any rate, it will be ultrasounded tomorrow AM when she isn’t pissing radiation. Best guess is some sort of ganglion cyst.

Question: Does anyone have any experience with cysts in this location, perhaps ones that were pushing on the perineural nerve?

Thanks in advance, I appreciate it!

UPDATE: This ended up not being fluid filled - they tried to aspirate it many times. A biopsy was pulled, and we are waiting on results.

UPDATE: The masses are all lymphoma. sigh

[Nathine]

It sounds like a ganglion cyst. classified under RMDs and caused by too many uninterrupted repetitions of an activity or motion, unnatural or awkward motions such as twisting the hock or fetlock, overexertion, incorrect posture, or muscle fatigue. Injections rarely help, and if fluid filled, the fluid can be withdrawn by needle but returns. Treatment usually consists of decapsulation and removal of the entire cyst.

[endlessclimb]

Unfortunately, after the ultrasound it is not liquid filled - it is a solid mass. We took a biopsy, as well as removing one of the lumps I’ve made a post about before (also solid, and very attached). Both with be sent to pathology for testing.

If/when the mass above her hock is removed, it can not be a standing procedure - she will have to be put under. Too close to too many critical nerves, tendons, and blood vessels.

Let’s just hope these masses aren’t cancerous, shall we?

[Bluey]

No experience with that, just jingles for your and your horse that the results are favorable.

[endlessclimb]

I added photos to the original post. Waiting on pathology reports.

[Toblersmom]

I haven’t dealt with horses or nuclear bone scan professionally in years, and it wouldn’t be appropriate to comment on a specific case’s medical status in this kind of situation, anyway. But, I can give some general education on why a lesion might be cold on the soft tissue and hot on the bone phase (of a bone scan, there’s a lot of other kinds of nuclear scans that aren’t done commonly in horses that radically change what kind of soft tissues are hot).

Soft tissue pathology is hot if it has a higher blood flow than the soft tissue in the area would have normally. Usually that means active, acute, inflammation, the same kinds of things you would expect to perhaps be literally HOT/warm if you passed your hand over them. Sometimes it means something like a vascular malformation, but that’s pretty rare.

In the bone phase, the body has incorporated the radioactivity (slang term in my world is “tech” to shorten “technetium 99m”) into the body the same way (roughly) it does phosphorous, and it’s built in to any hydroxyapatite crystals (the Lego bricks that make bone) the body is busy making since the injection happened. The body mostly is busy making HA crystals in bone. There’s plenty of it in teeth, too, but teeth don’t have a lot of turnover like bone does, so they’ll be pretty cold unless there’s something wrong. Normal warm-to-hot areas are places where the major weight bearing forces occur, and physes in youngsters. There’s also a relative appearance of warm vs cold depending on how much tissue is overlying the area. Abnormal spots are where the body is putting down more HA crystals than normal. Usually it’s a site of bony remodeling, like arthritis, navicular disease, stress fracture, osteomyelitis. However, there are certain soft tissue conditions that will have mineral and they will “light up” too. General (very general) classifications that may be seen (considering all species, not just horses) are sites of chronic inflammation or previous injury/insult (which may not be active enough to light up on the ST phase) developing “dystrophic mineralization”, oddball disorders of calcium/phosphorous metabolism like calcinosis circumscripta or calcinosis cutis, general disorders of Ca/Ph metabolism like parathyroid disease, and neoplasms (both benign and malignant) that have a tendency to lay down mineral (extraskeletal osteosarcoma, certain types of mammary and urinary tract tumors, etc).

[endlessclimb]

@Toblersmom

I haven’t dealt with horses or nuclear bone scan professionally in years, and it wouldn’t be appropriate to comment on a specific case’s medical status in this kind of situation, anyway. But, I can give some general education on why a lesion might be cold on the soft tissue and hot on the bone phase (of a bone scan, there’s a lot of other kinds of nuclear scans that aren’t done commonly in horses that radically change what kind of soft tissues are hot).

Soft tissue pathology is hot if it has a higher blood flow than the soft tissue in the area would have normally. Usually that means active, acute, inflammation, the same kinds of things you would expect to perhaps be literally HOT/warm if you passed your hand over them. Sometimes it means something like a vascular malformation, but that’s pretty rare.

In the bone phase, the body has incorporated the radioactivity (slang term in my world is “tech” to shorten “technetium 99m”) into the body the same way (roughly) it does phosphorous, and it’s built in to any hydroxyapatite crystals (the Lego bricks that make bone) the body is busy making since the injection happened. The body mostly is busy making HA crystals in bone. There’s plenty of it in teeth, too, but teeth don’t have a lot of turnover like bone does, so they’ll be pretty cold unless there’s something wrong. Normal warm-to-hot areas are places where the major weight bearing forces occur, and physes in youngsters. There’s also a relative appearance of warm vs cold depending on how much tissue is overlying the area. Abnormal spots are where the body is putting down more HA crystals than normal. Usually it’s a site of bony remodeling, like arthritis, navicular disease, stress fracture, osteomyelitis. However, there are certain soft tissue conditions that will have mineral and they will “light up” too. General (very general) classifications that may be seen (considering all species, not just horses) are sites of chronic inflammation or previous injury/insult (which may not be active enough to light up on the ST phase) developing “dystrophic mineralization”, oddball disorders of calcium/phosphorous metabolism like calcinosis circumscripta or calcinosis cutis, general disorders of Ca/Ph metabolism like parathyroid disease, and neoplasms (both benign and malignant) that have a tendency to lay down mineral (extraskeletal osteosarcoma, certain types of mammary and urinary tract tumors, etc).

This was super informative. Thanks a lot for writing that all out.

I have to say, I’m worried sick. Poor gal. Glad I did the scan, would have been the last place I would have suspected discomfort.

[Toblersmom]

Just to point out, the thing, whatever it is, may be the source of the lameness. Or it may be an incidental, although dramatic, finding. Radiologists who train other people to read imaging take a special evil delight in finding cases that bait the trainee into a “satisfaction of search” error. I’m not in a position for any number of reasons to comment which may be more likely for your horse. It’ll be interesting to see what the path results are.

[endlessclimb]

I’ll keep this updated… I know when I have an issue with my animals it soothes me to research and read other people’s tales of the same.

In regards to the findings, it is true that it may be completely incidental. Depending on what path finds, I will likely request a series of blocks above and below the mass (if possible) to confirm she goes sound when it isn’t part of the equation.

I have hock, stifle, foot, and spine xrays on this mare as well. Maybe I go overboard, but I would rather know than not know.

[Puddin_Pie]

Please keep us updated. Thanks for posting the pictures.

[endlessclimb]

It’s lymphoma. Waiting to know which kind. Haven’t decided what I’m going to do.

I’m pretty crushed.

[hoopoe]

Oh dear I am holding you and your dear friend in my heart

[Puddin_Pie]

Hugs and jingles.

[mroades]

Hugs and jingles

[Toblersmom]

Wow, just wow. Very unusual kind of case and one a teaching hospital may be interested in. There may be very effective chemotherapy and/or radiation therapy options depending not the details and whether or not the limb lesion is really the only one.

[endlessclimb]

@Toblersmom

Wow, just wow. Very unusual kind of case and one a teaching hospital may be interested in. There may be very effective chemotherapy and/or radiation therapy options depending not the details and whether or not the limb lesion is really the only one.

It isn’t, unfortunately. I posted a thread about other bumps the mare has - they’re all lymphoma.

https://www.chronofhorse.com/forum/forum/discussion-forums/horse-care/10138320-what-are-these-bumps

The bumps wax and wane. Some of the ones pictured in that thread aren’t there anymore. Meanwhile, others have formed.

Waiting to hear if it’s T or B cell, and given a treatment plan/cost/prognosis. She’s at a great weight (maybe a little chubby really), bright, alert, feisty. If it’s not too expensive, I’ll give a round of treatment a try because she’s otherwise really healthy. But I’m not going to throw money at a pit, as calloused as that may sound.

[Suspiria]

It’s not callous; it’s compassionate. Cancer treatments aren’t fun for the recipient, and critters don’t understand why they feel lousy.

I am so sorry you are having to deal with this. My barn owner just lost a Clydesdale to this diagnosis. He was an older guy, it was very advanced, and he was miserable–all things that made the decision easier to accept.

Hugs and jingles for you and your mare.

[EmilyM]

I’m sorry about the diagnosis. Whatever you decide, I’m sure you will do what is right for your horse whom you know better than anyone.

[endlessclimb]

She’s a badass mare, and will go out that way. Raced 47 times. I won’t let it get ugly before I make a call - she deserves it.

Meanwhile, her custom saddle is arriving the 29th. I’ll grab some stamps and put her tattoo number somewhere inconspicuous… may it always be hers, regardless of the outcome.

[Toblersmom]

@Suspiria

It’s not callous; it’s compassionate. Cancer treatments aren’t fun for the recipient, and critters don’t understand why they feel lousy.

Not all patients are the same. Not all cancers are the same. Not all cancer treatments are the same. Veterinary oncologists are keenly aware of quality of life vs. quantity of life balance issues, and help owners decide whether or not a given regimen fits the client’s perspective on where that balance falls. Some cancers are responseive to treatment protocols that have little or no clear side effects in veterinary patients, and result in a great extension of life and a great quality of life. Some have side effects or impacts that are comparable to interventions for non-cancer problems (e.g. recovery from abdominal surgery for cancer treatment, vs. for colic in a horse or a foreign body removal in a dog). Have I seen patients that are pushed, in my personal world view, too far for too little benefit, because the owners really want to treat the animal like a child? Sure I have. But for the most part a veterinary oncology ward is full of patients that happen to have cancer and are being treated for it, enjoying life and often in less pain and with more energy/joy than many of the patients seeing the orthopedic specialists or the cardiologists.