Neoplasms are diseases that develop when body cells divide uncontrollably. They affect all vertebrates, and as it turns out, they have been doing so for more than 210 million years. Among a great number of vertebrae of the Triassic amphibian Metoposaurus krasiejowensis found in Krasiejów, one specimen was identified with a case of a malignant neoplasm: osteosarcoma.