recently I discovered a growth on the inside of my 13 yr old Arabian geldings front leg just a few inches above the chestnut. its the shape and size of a large grape. upon touching it, it has a scabby shell, was somewhat hard but when pressed between my fingers it was squishy. upon further examination it looks to have blood inside as I peeled it back from the leg a little and some blood came out. no puss though. I also should add the growth is still covered with hair. I am wondering if this could be Melanoma and if not, what could it be?