Mysterious lump appeared

Question
Hi Jana,
We have a 10 month old Basset Hound, Lucy and we just found a mysterious lump that appeared.  The lump is on her right side, about 3 inches back from her arm and is on her ribs.  It is about the size of a walnut.  She does not even notice when I touch it.  It is hard; it does not feel like it is fluid filled.  Her behavior and eating habits have not changed either.  We have had her since she was 6 months old and this is the first that we have felt/seen it.  We are obviously concerned but before we panic or run her to a Vet we would like to get your opinion. Any information you have will be very appreciated.
Thank you,
Jessica

Answer
I wouldn't panic but I would take her to the vet and have it looked at. It could be a cyst, but those normally form on the top along the midline, or it could be a fatty tumor, but she is rather young for one of those.

There are many things it might be so your best bet is to have the vet look it over. Only a hands on exam will determine what it is.