Not ness an old injury,looks more of a recent gone sceptic...
"He who kills sow with piglets empties the forest of boar" My neighbours dad on new years eve 2011.
It was hard to touch, didn't feel liquidy. I thought it may have been an old injury that had tried to hel over itself.
To be honest i didn't really poke and prod it too much, just left it on the side of the track for the farmer to incinerate, as he does with all the foxes i shoot.