MONDO_0002629 (bone osteosarcoma) is a usually aggressive malignant bone-forming mesenchymal neoplasm arising from the bone. It may arise de novo or from a pre-existing lesion of the bone. Pain and a palpable mass are the most frequent clinical sign and symptom. It may spread to other anatomic sites, particularly the lungs. Also known as: osteosarcoma of bone, osteosarcoma, somatic, osteosarcoma, somatic mutation, primary osteosarcoma of bone.