Growing Lump on Neck

Hi, Our 12 year old female dog has has a small lump on her neck for years which used to drain so we presumed it was a cyst. It came back last year and since then its steadily growing larger. It almost looks like it filled with fluid. It has 2 raised bumps on the larger lump, but i can physically move it about and pretty much get my fingers all the way under move it, with no pain to the dog or anything. Which leads me to believe it is a cyst. Would it best to get this checked and removed? 

Hello!  I am going to assume that this is a skin lump.  There is an unknown here; we don't know whether this lump is a) a cyst or b) for example, a cancer or lymph node with cystic areas.  The only way to properly find out would be to remove and sample it.  Biopsies of various kinds may also provide clues. So: assuming that it is a) a cyst, removing it will carry some risk but potentially have the advantage of the cyst being gone.  If you leave it there, you may still not 100% know that it is safe to leave.  It may develop in a negative way, or  grow bigger until it catches on things, or it may remain as it is. If it turns out to be - say, a cancer - leaving it there may be a bad thing because you would still not know that the cancer was there.   And removing it may solve the problem, or it may indicate that further treatment is needed, or, in some situations, that the problem couldn't simply be taken away. You could draw this out as a tree of possible paths, but for me, if the anaesthetic risk was relatively low, then investigating and finding out what the lumps identity is, possibly through removal, would be my choice based on what I can see. However this is a decision better talked over with your vet, who can feel the size of the lump and the local lymph nodes etc and therefore has more information on which to base this multifactorial decision. I hope that that helps.

(correction - having now looked at the picture, it is unlikely that this is a lymph node as they would be deeper.  One can't rule between a tumour and a cyst simply by looking.  I agree with you that initially it does look like a simple cyst, but it is obviously changing and the caveat that it is impossible to know simply by looking remains).

Thank you for the advice, we are getting her booked in to be checked. She does other lipomas on her body but this one is different. It is also I probably should of said on the back of her neck, between the very back of her ear and where her collar sits.