Fatty Lump on Outside of Knee?

About 2 days ago I noticed a fatty lump on the outer side of my horse's knee. It's about the size of a golf ball, but it's not hard. It feels really fatty/fleshy. I hosed with cold water yesterday to see if I could get it to go down, but it didn't.

Here's the thing - she's not limping, she's out in the pasture running, jumping,and kicking up her heels, I can poke and prod at this thing and there's no pain response from her at all, it's not hot and there's no heat or swelling in any other tissue. I checked her hooves and she's good. She also has this mannerism that she does when she eats (always has, since she was a baby) where when she eats her grain she has to stand on 3 legs. She just picks up her left front and stands there with it tucked up against her and her head in her bucket (she's not pawing or impatient or anything...just standing there like a flamingo). This lumpy thing is on her right front, so she actually stands there and puts a lot of weight on the leg with the lump and has no trouble and shows no signs, whatsoever, that this thing is bothering her.

Any ideas on what it could be?

Hard to say with out seeing it, or feeling it but.....

It could be a lipoma (collection of fat cells) or...

Hematoma (collection of blood outside of blood vessels)...with a hematoma, treat as with....Rest, Ice (cold hose), and compression. She could have gotten kicked, or bumped herself, and you weren't aware, but burst some blood vessels diuing the incident.

Both are harmless, and generally go away on their own, or, remain, and are more a blemish than anything. (hematomas usually go away, but the odd one stays....just isn't as large as the initial bump.

That being said, may want to get your vet out to check to ensure that there isn't anything seriously wrong...more than likely not, but always safe than sorry IMO

Dont stressssss

My old horse has that on his left front

It is caused by them laying them when getting up pinching it with the back hoof
So my farrier says\

My vet said leave it it cause no problem at all,

but you can get them removed if you dislike the look, but besides hat its nothin to worry they can come nd go