Primary Bone Osteosarcoma

**Semantic type:** Neoplastic Process

**Definition:** A usually aggressive malignant bone-forming mesenchymal neoplasm arising from the bone. It usually involves the long bones and predominantly affects adolescents and young adults. Pain and a palpable mass are the most frequent clinical sign and symptom. It may spread to other anatomic sites, particularly the lungs.

**Synonyms:** - Primary Osteosarcoma of Bone