As I said earlier, we took Kuron up to the Royal Veterinary College before we went away, and they did some more tests - mostly repeats of the earlier ones to see if anything had changed - and the ultrasound scan showed he had an enlarged pancreas and nodules on his liver. So they decided to forego the gastroscopy and open him up to see what was going on.
Apparently the surgeon who did the operation had never seen nodules like this on a cat's liver before, which is par for the course.
Anyway, they took biopsies of his liver, pancreas and digestive bits and bobs, and it turns out he has inflammatory bowel disease and very mild hepatitis and pancreatitis which may well be linked to the inflammation. The nodules, whatever they are, are not malignant.
The IBD is the reason he was losing weight, and there's a fair chance that it can be managed with steroids. We brought him back on Tuesday evening - shaved in some different places, in particular his tummy - and the doctor who was treating him told us to keep an eye on him until Monday. If he's not behaving weirdly by then, he starts the 'roids. One tablet in the morning, one in the evening, for a few months. If that works, we start tailing the dosage off, although he may have to have some kind of medication for the rest of his life - we don't know yet.
While he was at the hospital, they fed him the kind of diet we'd been feeding him before all this started, and he didn't throw up once. Which suggests he was just intolerant of the single protein-single carbohydrate diet.
So, it's not cancer, it's not feline HIV, it's not feline leukaemia. It's only inflammatory bowel disease.
And they phoned us every day while we were in Poland with updates, even when there was nothing to tell us. If I ever get really sick, Bogna has instructions to drive me up to the Royal Veterinary College. I can't speak highly enough of them.