A paleontologist, a medical pathologist and an orthopedic surgeon enter the museum. No, this is not the beginning of a joke, but the research team that diagnosed the first confirmed case of aggressive bone cancer in a dinosaur.
The specimen in question is a petrified shin bone torosaurs, a herbivorous horned dinosaur that lived and died approximately 76 million years ago.
What looked – at least at first glance – like a poorly healed fracture turned out to be a tumor that swallowed the upper half of the animal’s tibia or fibula. The centrosaurus was diagnosed with osteosarcoma; it is the most common type of bone cancer in humans, but marks the first confirmed case of any malignant cancer we found in a dinosaur.
“Here, we show the unmistakable signature of advanced bone cancer in [a] A 76-million-year-old dinosaur with horns ̵
Shin bone, with the main tumor mass in yellow. (Danielle Dufault / Royal Museum of Ontario / University of McMaster)
In humans, osteosarcomas often affect growth-promoting teens and young adults. If metastases of osteosarcoma – growing outside the bone – most often spread to the lungs, but can also form tumors in other bones, and even the brain.
As curious as we may be about the evolution of diseases such as cancer, soft tissues such as tendons, ligaments, bone marrow, and tumors are rarely preserved in fossils. Given a few years – let alone a million – these tissues will disintegrate. So even if dinosaurs were regularly affected by cancer, any diagnostic samples would be difficult to find.
Scientists have encountered similar cancer-like symptoms to dinosaur fossils. Unusual lesions in the caudal vertebrae of a young adrosaurus resemble a condition called Langerhans cell histiocytosis, a complex cancer that leaves room for discussion about its manifestation. In the case of this latest discovery, the malignancy is far clearer.
The fossilized bone of the tibia of cancer has been detected C. open was discovered in Dinosaur Park in Alberta, Canada in 1989 and was housed in the Royal Museum of Paleontology in Tyrrell, outside Calgary, until its recent reaction.
Cross sections of C. open The bones were first taken with a CT scan, the same machine used to identify bone fractures and tumors in humans. The “slices” of the X-ray image were reconstructed to see how the tumor grew through fossilized bone.
In fact, it had spread through the bone quite widely, which the medical team took as a sign that this centrosaurus had been living with its cancer for quite some time.
“This finding reminds us of the common biological connections throughout the animal kingdom and supports the theory that osteosarcoma tends to affect bones when and where they grow fastest,” said Seper Echtiari, an orthopedist who is studying to become a surgeon at McMaster University. Toronto, who studied the fossil.
Because the cancer was so advanced, researchers believe it may have spread to other parts of the dinosaur’s body, but we don’t have any of these tissue samples – such as the lung fungus – from this ancient animal, for to be sure.
“The tibia bone shows advanced advanced cancer,” says paleontologist David Evans. “Cancer would have a crippling effect on the individual and would make him very vulnerable to the huge predators of the tyrannosaurus of that time.”
After imaging the shin cancer, the thin sections were carefully cut from the fossils and compared to normal C. open fibula, along with a case of human osteosarcoma, from a 19-year-old man who had it in his lower leg.
In their paper, the authors note that “similarly advanced osteosarcoma in a patient left untreated would certainly be fatal.”
But they suspect that the dinosaur died with its flock, probably in a sudden flood, because the fossil was found in a massive bed. Centrosaurus bones.
“The fact that this plant-eating dinosaur lived in a large, protective herd may have allowed it to survive longer than it would normally have in such a devastating disease,” Evans said.
And when we often marvel at the age of the dinosaurs and their size, large and small, this latest medical discovery brings the plight of dinosaurs closer to home.
“Evidence suggests that malignancies, including bone cancer, are rooted quite deeply in the evolutionary history of organisms,” the authors conclude. Yes, even dinosaurs.
The study was published in a medical journal Lancet Oncology,,