This morning in a make-up cat attention session, I found lumps near 2 of Agatha's nipples, and one of the nipples itself is enlarged. I managed an appointment with Dr. Dunn this afternoon, and it is probably either cancer or (I think I got the right phrase) mammary hyperplasia. Feline mammary cancers have a very bad prognosis--generally they metastasize, and the life expectance is 1-2 years with aggressive treatment. The hyperplasia, if I have the diagnosis right, can have various effects on quality of life too, but is not generally fatal in itself. Dr. Dunn thinks Agatha does not have any sort of treatable infection causing the lumps, in any case.
We're going to do nothing. Not going to worry about the exact cause, and just treat any secondary effects as they show up. Aggie's life expectancy at age 17 and with the kidney disease worsening isn't going to be significantly different either way, and trying to treat a cancer would definitely be too hard on her.
She's very annoyed with me for the vet visit on top of the 8-night trip to Disney World, and is hiding under the guest bed. Fred, on the other hand, who had her annual checkup this morning, is actively seeking attention just as she was before the vet trip.
Interesting side note: Fred is extremely vocal at home, complaining, demanding, or just talking. She gave maybe 2 meows on the trip to the vet, and was completely silent while there and on the way home. Agatha, who speaks only on rare occasions to demand some action on my part, cried all the way there and some on the way home, even though she was on my lap most of the return trip. Some sort of inverse action caused by the cat-carrier, perhaps...