Most veterinary malpracticioners recommend draining them:

http://www.rottweiler.net/forums/vet...1-hygroma.html
hygroma


He keeps his dog in a CRATE???
Who the **** puts a dog in a crate? Dogs belong on the furniture! On the
couch licking your face as you try to watch TV or on the bed farting in your
face as you try to sleep. My dog and cats get to go where the hell they
want. And the more inconvenient that is for me, the more they want to go
there. If I tried to put any of them in a crate my arms would get peeled
like bananas.