Epiphyseal bone lesions
Overview
- Epiphysis is a key diagnostic filter: Only a select set of lesions occur here.
- Knowing these gives high-yield diagnostic/exam power.
- Epiphyseal equivalents: Patella, greater trochanter, calcaneus, carpals, and other apophyses.
Epiphyseal lesions
| Lesion | Typical Age | Key Imaging Features | Clinical Pearls |
|---|---|---|---|
| Chondroblastoma | 10–25 (open physis) | Lytic, well-defined, thin sclerotic rim; may have edema | Most common true epiphyseal tumor in kids/teens |
| Giant Cell Tumor (GCT) | 20–40 (closed physis) | Lytic, eccentric, non-sclerotic border; may extend to subchondral bone | Occurs after physeal closure; pain, swelling |
| Clear Cell Chondrosarcoma | 20–40 | Lytic, expansile, mild sclerosis, may mimic GCT | Rare, malignant, older pts than chondroblastoma |
| Infection (Epiphyseal OM) | Any (esp. kids) | Lytic or ill-defined, may cross physis | May have systemic signs, fever |
| Geode (Subchondral cyst) | 40+ (OA age) | Well-defined cystic lesion at articular surface | Associated with osteoarthritis |
| Chondromyxoid fibroma | Rare in epiphysis | Eccentric, lobulated, sclerotic rim | Usually metaphyseal, but can be epiphyseal |
Epiphyseal Equivalents
- Patella:
- GCT
- Chondroblastoma
- Clear cell chondrosarcoma
- Apophysis (e.g., greater trochanter, calcaneus):
- Chondroblastoma
- Rarely GCT or others
Pearls
If it’s in the epiphysis, think of:
- Well-defined lytic lesion in epiphysis (<20y; skeletally immature) → Chondroblastoma
- Lytic, eccentric, (young adult; skeletally mature) → GCT
- Malignant, older young adult (20-40y) → Clear cell chondrosarcoma
- Fever/systemic, fuzzy border → Osteomyelitis (brodie's abscess)
“Epiphysis = VIP filter. Metaphysis/diaphysis = everyone’s invited, use other features.”
