Parosteal Osteosarcoma

**Semantic type:** Neoplastic Process

**Definition:** A low grade malignant bone-forming mesenchymal neoplasm arising from the surface of the bone. It usually affects the distal posterior femur, the proximal tibia, and proximal humerus. Painless swelling is the usual clinical sign. Most patients are young adults and the prognosis is usually excellent.

**Synonyms:** - Juxtacortical Osteogenic Sarcoma - Juxtacortical Osteosarcoma - Juxtacortical osteosarcoma - Parosteal - Parosteal Osteogenic Sarcoma - Parosteal osteosarcoma