A team of researchers from the University of Washington has discovered a benign tumor in the jaw of a 255-million-year-old mammalian beast called gorgonopsian or gorgon.

The research, published in the journal JAMA Oncology, states that the rare find could be one of the oldest tumors and cancer cases ever discovered. The team discovered the tumor upon slicing the gorgon's jaw found in Ruhuhu Valley, Tanzania. The said cancerous tumor was located at the root of the creature's jaw near small teeth-like structures.

The said dental tumor had a compound called odontoma, which is usually characterized by ectopic miniature teeth that were also present in the fossil. Odontoma, usually found in mammals, is highly dangerous and requires surgery to remove it.

"We think this is by far the oldest known instance of a compound odontoma. It would indicate thi is an ancient type of tumour," Professor Christian Sidor from the University of Washington told Daily Mail in an interview.

Meanwhile, paleobiologist Megan Whitney recalled to Reuters that the discovery was a surprise for them. She said, "There was no indication that there was a tumor in this jaw. It looked normal before we cut it open. It was pure luck that we found the tumor."

Gorgnopsians or gorgons are ancient predators that existed long before the dinosaurs roamed Earth about 270 million to 253 million years ago. The species was wiped out during a mass extinction that happened in the late Permian Period.

The discovery of the fossilized cancerous tumor in the gorgon's jaw shows that tumors have already existed in ancient mammal ancestors. Whitney also said that this discovery paves way in "understand[ing] the evolution of diseases in deep time and have the potential to provide clues as to the causes of diseases that afflict humans."