Asynchronous Multifocal Osteosarcoma

**Semantic type:** Neoplastic Process

**Definition:** A bone osteosarcoma affecting multiple skeletal sites, with multifocal lesions discovered between 6 and 24 months after the appearance of the initial tumor. Patients with asynchronous tumors have a better prognosis than those with synchronous osteosarcomas.

**Synonyms:** - Asynchronous Multifocal Osteogenic Sarcoma