Last week-end Ken noticed what felt like a cyst on Leo's chest. We watched it for a few days. It got smaller and then larger again. I called the vet on Thursday and made an appointment for Friday. We feared the worst, that it was a tumor.

The vet did a thorough exam and said she was having a hard time hearing his heartbeat. She recommended x-rays to see if she could tell what was going on.
It turned out to be a good news/bad news scenario. The good news was there was no tumor in his chest and his lungs were clear. The bad news was that that information didn't answer any of the questions about the cyst or his heart. She recommended a test of the fluid in the cyst, blood work, and a thyroid test.
Last evening I talked at length with the vet on the phone. Again, there was good news and bad news. No sign of cancer. The cyst may be an indication of something deeper or it could be a reaction to an injury and will heal in time. There is no problem with his thyroid, but that means that he probably has the beginnings of heart disease. The lab work did show the start of kidney disease, which means we will be starting him on special food that is very low in protein. Poor Leo ~ he loves his protein-filled wet food and little tastes of meat as special treats.
There are good signs: he's not having trouble breathing and none of his habits have changed. Our best estimate is that he's about 14 years old, so all things considered he's doing okay.
It is silly to be so attached to little guy. I asked him last week who I would talk to if he wasn't around. He looked at me as if to say, "What's for dinner?" So we will take it one day at a time and do what we can to keep him as healthy as possible.