We have similar stories to both of yours. Our girl Bailey had a growth near her elbow that the vet always kept an eye but never seemed concerned. It changed in shape and size, and became a problem as she'd bump it or make it bleed during normal activity. The vet removed it and sent it off to be tested and it was hemangiosarcoma. I can't remember the grade, but it came back with clear margins.
Our other dog Trooper-has a couple of those floating fatty deposit looking things that we have the vet look at...and again-no concern. The difference is-with Trooper we've had them aspirated (and they've come back as nothing) The thing on Bailey, to me, didn't look like it could be aspirated. Now, I basically have no medical animal knowledge-so I could be completely wrong...but it kind of looked like a weird skin tag.
I went back and looked-it was grade 1 stage one: viewtopic.php?f=5&t=149075&hilit=+hemangiosarcoma
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