Paleontologists initially thought the bone’s strange shape was due to a fracture that hadn’t healed cleanly. 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 conclusion: The dinosaur suffered from osteosarcoma, a cancer that, in humans, primarily attacks teens and young adults. The disease causes tumors of immature bone tissue, frequently in the long bones of the leg.
More: "Rare Malignant Cancer Diagnosed in a Dinosaur" (Royal Ontario Museum)
images: bone, Royal Ontario Museum/McMaster University, Centrosaurus, Fred Wierum (CC BY-SA 4.0)