This deformed bone is the first clear example of a malignant tumor diagnosed in a dinosaur.
But a new study, published today in The Lancet Oncology, compares the internal structure of the fossil (above) with a bone tumor from a human patient to seek a diagnosis.
The disease causes tumors of immature bone tissue, frequently in the long bones of the leg.
Scientists, including paleontologists, pathologists, a surgeon, and a radiologist, examined the full fossil with high-resolution computerized tomography scans and examined thin sections under the microscope to evaluate the structure of the cells.
However, because the fossil was found in a bone bed with lots of other Centrosaurus specimens, the dinosaur likely died in a flood with the rest of its herd and not from the cancer.