So, it's a puzzle. We brought Gracie to the veterinarian because she was acting like she might have stones, or a kidney/bladder infection. She'd never appeared to have any other problems, certainly nothing like what you might expect from a penny in the stomach. It was as much a surprise to the vet as it was to us! Gracie's been a 'cast iron' kitty her whole life - she'd never previously been to the vet for anything but her annual shots.

Gracie is ten years old. We got her at the Marin Humane Society when she was about six weeks old, in August 1991. The penny she swallowed is dated 1980, so it provides no 'benchmark' earliest date she could have swallowed it. She must have been an adult when she swallowed it, as her esophagus would have been too small as a kitten. Heck, it's hard to imagine her swallowing it even as an adult, she's a smallish cat, an Abyssinian/Tabby mix. The penny could have been in there for up to eight/nine years, we suppose.

Considering how small it had become from erosion, she had to have swallowed it at least a couple of years ago, minimum. Copper is non-reactive in hydrochloric acid (stomach acid). However, most pennies aren't pure copper - those dated before 1982 are 97% copper, 3% zinc. Zinc is reactive in HCl. There's no way to determine what other reactions may take place in the presence of assorted foods of varying Ph, but generally I'd think it would be a pretty slow process. Unfortunately, Gracie steadfastly refuses to share the details, preferring to search out sunny spots to laze around in.

Regarding the penny, it's a good thing it wasn't a post-1982 penny. Since 1982, all pennies have been minted as a core of solid zinc, with just a few microns-thick cladding of copper. Had she swallowed such a penny, it would have eroded quickly, and would have probably been deadly in short order - zinc is quite toxic to kitties.

The sad news however, is that when they removed the penny, they also took a biopsy of her stomach and duodenum; the lab analysis of the duodenal biopsy showed she has lymphoma. She is asymptomatic, however, so we're hoping we can just keep her well-fed, full of catnip, and as comfortable as possible for what time remains for her -- which could be anywhere from a few months, to a couple of years. There is 'kitty chemo', but we can't see putting her through that, for the relatively small increase in life-span it might provide, balanced against the distress she'd suffer with constant shots and pills.

Thanks go to Doctors Hinkle and Leavey, of Animal Hospital of Cotati, for the loan of the radiograph, and for their kindness and professionalism - and that of all their wonderful staff.