Ellie-May had been missing for two days before the grim discovery was made by a member of the public in Lincoln Drive, Cannock.
The RSPCA has launched an investigation to find out whether the pet has been killed by a human or a wild animal.
The owner of the 18-month-old black and white cat, Brenda Hearndon, said the news of her last moments was "awful".
The 74-year-old said: "I have had Ellie-May since she was dumped 10 months ago with 12 kittens and she worked so hard bringing these kittens up.
"She was a very timid cat but she was affectionate towards me.
"It is so sad because she was just starting to enjoy life, going outside and doing what cats like to do, but now something like this has happened and it is awful."
RSPCA inspector Kate Levesley said: "We do not know for certain how Ellie-May died, whether it was by the hands of a cruel human being or whether she died naturally and had started to be scavenged by wild animals.
"However we cannot rule anything out. If this was done deliberately, it does not bear thinking about how terrified Ellie-May may have been in her last moments."
Anyone with information is urged to come forward.
The body of a cat missing its head and tail has been found in a Staffordshire garden.