Take-Away Points
■ Major Focus: To detect and diagnose malignancy in the dinosaur fossil record by using radiologic and histopathologic techniques.
■ Key Result: The gross, radiologic, and histologic appearance of a Centrosaurus apertus fibula fossil dated more than 75 million years ago has characteristics consistent with osteosarcoma when compared with a normal C. apertus fibula fossil and human osteosarcoma.
■ Impact: Cancer is a disease that not only afflicts humans in the modern age but is a prehistoric pathology with deep evolutionary origins.
Paleopathology is the study of ancient disease, yielding insights into the evolutionary history of modern diseases that afflict humans, including cancer. Research into the prevalence of cancer in prehistoric organisms is limited by the low probability of cancer preservation in the fossil record and reticence to destructively analyze otherwise rare specimens. Noninvasive morphologic and radiographic techniques have been used to identify evidence of cancer, most recently osteosarcoma in a 240-million-year-old reptilian amniote (1).
In a correspondence published in Lancet Oncology, Ekhtiari and colleagues used histologic sectioning in addition to high-resolution x-ray CT to analyze two different Centrosaurus apertus fibulae fossils, the pathologic sample and a normal control. Relying upon interdisciplinary expertise in musculoskeletal oncology and human pathology, the authors confidently diagnosed osteosarcoma. The pathologic fibula fossil, excavated from the Dinosaur Park Formation in Alberta, Canada, in 1989, dates approximately 77.0–75.5 million years ago. The lesion in the fibula initially was thought to represent a healing fracture callus. However, CT scans of the specimen yielded radiologic findings most compatible with osteosarcoma, such as presence of aggressive periosteal reaction (Codman triangle), cortical and medullary disruption, and disorganized sclerosis within the lesion. Histologic examination demonstrated poorly matured bone and permeative, bidirectional and distant invasion compatible with osteosarcoma. These radiologic and histologic features shared similarities with a human above-knee amputation surgical specimen of high-grade conventional osteosarcoma of the fibula, which was analyzed by micro-CT and conventional histopathologic staining.
In conclusion, this is a novel and modern multidisciplinary approach to detection and diagnosis of cancer in the fossil record and the first to report osteosarcoma in a dinosaur. This adds to our understanding of cancer as not only a modern human disease phenomenon, but a prehistoric pathology with deep evolutionary origins.
Highlighted Article
Ekhtiari S, Chiba K, Popovic S, et al. First case of osteosarcoma in a dinosaur: a multimodal diagnosis. Lancet Oncol 2020;21:1021–1022. doi: https://doi.org/10.1016/S1470-2045(20)30171-6
Reference
- 1.Haridy Y, Witzmann F, Asbach P, Schoch RR, Fröbisch N, Rothschild BM. Triassic cancer—osteosarcoma in a 240-million-year-old stem-turtle. JAMA Oncol 2019;5(3):425–426. [DOI] [PMC free article] [PubMed] [Google Scholar]