Conventional intramedullary chondrosarcoma
They typically occur in the 4th and 5th decades with a slight male predominance 1.5-2.0:1.
At diagnosis it is typically a large mass, usually over 4 cm in diameter. When arising in long bones (most common location) it typically involves more than 50% of the length of the shaft.
Typically chondrosarcomas present with:
- pain: present in 95% of cases, often long standing and worse at night
- palpable mass: present in 28-82% of cases
- pathological fracture: present in 3-17% of cases
Histologically, the tumor grows as multiple hyaline cartilage nodules with central high water content and peripheral endochondral ossification. This accounts for not only the high T2 MRI signal but also for rings and arcs calcification and popcorn calcification on CT and plain film.
- long bones (45%)
- pelvis (25%)
- ribs (8%)
- spine (7%)
- scapula (5%)
- sternum (2%)
- skull (uncommon)
For imaging findings please refer to the article on chondrosarcoma.
- low-grade conventional chondrosarcomas can be difficult to distinguish from an enchondroma, as both grow in a nodular pattern and result in scalloping of the inner surface of the cortex
- scalloping of greater than two-thirds of the cortical thickness, cortical breach and soft tissue mass beyond the confines of the bone are useful distinguishing features
- see article: enchondroma vs. chondrosarcoma