A terrier-type dog, he was found confused and wandering in a circle in Greenfield Gardens, in Elton, on Sunday, July 30.
He was taken to a vet where he was examined. Sadly, he was so poorly that the vet put him to sleep on humane grounds.
Now the RSPCA is urging people to come forward with information about the dog and how he came to be in this state.
RSPCA inspector Leanne Cragg said: “This poor dog, who was around 16 years old, was totally blind and emaciated and had a huge tumour on his stomach and testicle. He would have been so uncomfortable and in pain.
“We do believe he has been owned until recently, as he had short claws which looked as though they had been recently clipped.
“It is so sad that this dog ended up in this way – he was in such an awful state.”
Anyone with information should contact the RSPCA on 0300 123 8018, leaving a message for Inspector Cragg.
To help the RSPCA continue rescuing, rehabilitating and rehoming animals in desperate need of care, visit: www.rspca.org.uk/give or text LOVE to 87023 to give £3 (Text costs £3 + one standard network rate message).