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Guinea Pig Lump/growth


New Born Pup
Sep 18, 2017
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My Guinea Pig has a growth/lump on the centre of his back. It has a scab in the centre and in my opinion looks like it is filled with something, as if I squeezed it (which I don't plan on doing) something would come out. This is especially due to the scab in the middle seeming like it goes deep, as if it goes deep within the bump rather than sitting on top. Has anyone had anything similar, or know what it is? I'm a student and really can't afford anything extreme. My parents have suggested using hydrogen peroxide on it.



@Brooklyn That looks very much like a sebaceous cyst that has previously burst and closed up again.

It shouldn't cause any problem at the moment if you leave it alone (don't use peroxide on it).

I suggest starting a small savings fund as at some point in the future it's going to burst again.

I had a boar that had one for years. It burst every couple of years or so, and the vet checked it to see if it was infected. Thankfully it was fine.

But it did yet to a point where it got too big. It still never bothered him but we opted to have it removed as the hole/scab was getting larger each time.

So, eventually you'll need to see a vet about it. Hopefully it will stay dormant for a long time.


Adult Guinea Pig
Aug 10, 2009
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Looks like a sebaceous cyst that has previously burst and dried up!
I have a couple of pigs with theses and l just leave well enough alone,

If yours has been like this for a while then in all probably it is dormant, and will remain that way,

Squeezing and flushing could cause it to become infected! Just look at it every week or so for signs of activitie