Hi Erin,
I am so sorry for you and your pup. The others have offered you some good advice. There are also bacterial infections that can cause enlarged lymph nodes. You could take her to another vet and have them run a complete blood panel and have a sample from the lymph node sent to a pathologist. The result might still be lymphoma. A close family member’s dog had lymphoma, did chemo and it bought him some extra months with his wonderful dog. Unfortunately, the dog had the more aggressive lymphoma, but the other forms respond very well to chemotherapy. It may not cure, but it will buy you a lot more time.
In regard to the food, if the canned is giving diarrhea, you might want to cut back and instead give a combination of the kibble that the dog has done well on with some canned and add warm water. You can let it sit long enough to soften the food so eating won’t be a problem. The steroids are making her hungry. Whatever you decide to do, the best thing you can do is make the dog comfortable and feed something that won’t cause diarrhea. She doesn’t need digestive issues along with a life threatening disease. Best wishes to you and your pup!
Here’s a link regarding lymphoma that might help answer your questions:
Canine Lymphoma Types
