Mark,
Honestly it sounds like she is due for a geriatric bloodwork and screening. It's unusual for dogs to lose weight as they age, especially in the face of a good appetite, so that is concerning. Also, the seizures could be a sign of maldigestion or her liver not detoxifying her blood. Or her seizures could be a separate issue. But the more times a dog has seizures the more frequent and serious they can become.
Lots of dogs are treated very successfully with oral medications for seizures. Also, since her masses were lipomas, I am not too concerned with the masses. I suggest keeping a little map of her body showing the sizes and placement of her lumps/bumps. Check it every month or so and look for growth, change in shape or size, or new bumps. It is hard to be objective about our own dogs when we see them everyday. A map will help eliminate the guess work.
I hope this was helpful for you. A quick trip to the vet with minimal bloodwork and maybe an xray will give you all the answers you'll need. You'll be glad you did.
Dr Michael
Dog Veterinarian
4+ years additional specialty training after vet school