extraskeletal osteosarcoma
Rare malignant bone-forming tumor arising in soft tissues without connection to underlying bone.
Full Definition
Extraskeletal osteosarcoma is a rare variant of osteosarcoma that arises in soft tissues without any connection to underlying bone or periosteum. This tumor produces malignant osteoid and bone formation within soft tissue structures, most commonly affecting the thigh, buttock, or retroperitoneum in older adults. The diagnosis requires histological confirmation of malignant osteoid production in the absence of any skeletal involvement. Treatment follows similar principles to conventional osteosarcoma but presents unique challenges due to the soft tissue location and tendency for local recurrence. The prognosis is generally worse than skeletal osteosarcoma.
Usage
Usage note: Emphasize the absence of bone involvement in diagnostic documentation.
In Context
- "Histopathology confirmed extraskeletal osteosarcoma with malignant osteoid formation." — Pathology report
- "The retroperitoneal mass was diagnosed as extraskeletal osteosarcoma despite no bone involvement." — Multidisciplinary team meeting