Epidemiology
More common in adults; it may involve the pelvis, proximal femur, shoulder, or ribs. In an adult cartilaginous lesion, progressive pain, growth, or cortical involvement change the level of suspicion and may change management.
Basic features
A cartilage sarcoma whose behavior varies widely depending on its histologic grade. It usually causes deep, dull pain that persists for months, often also at rest or at night, rather than the mechanical pain of a worn joint; in the pelvis it can grow considerably before it hurts. Most arise de novo, but a minority arise in a pre-existing osteochondroma or enchondroma: that is why new pain or growth in one of those known lesions must be reassessed.
Usual treatment
Surgery is the mainstay, and how extensive it needs to be depends on the grade and the location: for low-grade lesions in the limbs, curettage (scraping the lesion out from inside the bone) or even monitoring with imaging is often enough, while wide margins are reserved for higher grades and for any lesion of the pelvis or axial skeleton, even grade 1. Chemotherapy and radiotherapy play a limited role, except in specific subtypes or situations.
Outcomes and prognosis
The outlook depends above all on the grade: it is favorable in low-grade lesions (which in the limbs are now called an atypical cartilaginous tumor), intermediate in grade 2, and guarded in high-grade disease, being very unfavorable in the dedifferentiated subtype. High-grade, pelvic, or metastatic disease requires close monitoring.