Video and photos shared by In Defense of Animals shows the German shepherd with zip ties around its mouth and neck.
According to the group, the dog was found by hikers last Wednesday. They removed the zip ties and called animal control and law enforcement officials.
Los Angeles County Animal Care and Control officials said in a statement the dog -- a 7-year-old male who has been named Argon -- was found about 250 feet down the side of the road near the 500 block of North Malibu Canyon Road.
"The dog had a lot of inflammation, and warts/skin tags on the stomach and groin area," according to the agency. "The (animal control) officer suspected the dog had been exposed to poison oak."
Argon was taken to Palmdale Animal Care Center for medical treatment then taken to the county's Agoura Animal Center.
Veterinarians believe he may have lymphoma. He's now undergoing further testing to see if it's treatable.
Fleur Dawes, communications director for In Defense of Animals, said in a statement the group is grateful for the hikers' actions in saving the dog, but added, "our efforts must continue."
"This dog was left to suffer and die in a remote location," Dawes said in a statement. "We urge anyone with information about this cruel act to come forward. We are determined to find the person responsible for this horrific abuse and hold them accountable since they are a danger to others."
Dawes asked anyone with information to contact IDA at 415-879-6879.
City News Service contributed to this report.