Fossilized femur reveals 240-million-year-old case of rare bone cancer

Researchers have discovered one of the oldest known case of bone cancer via a 240-million-year-old fossil, a study has revealed. The malignant tumor was identified in the femur of a Pappochelys, a type of extinct reptile similar to modern day turtles. The fossil was recovered in Germany from an ancient lake bed, later ending up in the Stuttgart State Museum of Natural History.

The study, which was recently published in JAMA Oncology, details the oldest known case of bone cancer in an amniote, a group that includes reptiles, mammals, and birds. The Pappochelys belonged in the 'reptile' category, having been something like a turtle without a shell.

Of note was the femur fossil's substantial, atypical growth, which resembles something somewhat jagged and wavy. Research was conducted to try and determine what caused this unusual appearance, including micro-CT scans conducted at a university hospital.

In cases like this, a bone fossil with an unusual appearance is often due to an injury the creature had experienced, such as a broken bone that healed poorly. The micro-CT scans revealed this wasn't the case with the femur, however, as there was no evidence of a break under the jagged portion.

Other possible causes were considered and ruled out, eventually narrowing the answer down to a final possibility: bone cancer, specifically an osteosarcoma. This same type of bone cancer can be found in humans, though it is considered quite rare.

The fossil provides rare evidence of the cancer's existence long before modern pollutants and unhealthy lifestyles. Though there's little evidence of the disease in the fossil record, this finding shed light on the condition's lengthy history.