Diaphyseal Lesions
Overview
- Diaphysis = shaft of long bone, less "special" than epiphysis but still a useful clue
- Most bone tumors can occur here, but some have a predilection for diaphysis
- Metaphyseal lesions can grow into the diaphysis in skeletally immature patients (open physis)
- Location alone rarely diagnostic—use age, margin, matrix, and periosteal reaction
Classic Diaphyseal Lesions
| Lesion | Typical Age/Notes | Key Imaging Features / Pearls |
|---|---|---|
| Ewing sarcoma | Kids/teens (5–20) | Permeative, onion-skin periosteal rxn, soft tissue mass |
| Lymphoma of bone | Any age, peak adult | Lytic, permeative, minimal periosteal rxn, may be subtle |
| Adamantinoma | Young adult (10–40), tibia | Eccentric, multilocular, tibial diaphysis classic |
| Fibrous dysplasia | Any age (peak <30) | "Ground glass" matrix, can involve entire shaft |
| Multiple myeloma | 40+ | Multiple lytic "punched out" lesions |
| LCH | Kids | Lytic, beveled edge, "button sequestrum" |
| Osteoid osteoma | 10–30 (kids/young adults) | Cortical nidus, sclerotic rim, nocturnal pain |
| Others… | — | Chronic osteomyelitis, mets, fibrosarcoma, Enchondroma |
Pearls
- Diaphysis = classic for Ewing, adamantinoma, lymphoma, fibrous dysplasia, osteoid osteoma
- Multiple myeloma can involve any part but likes shafts in long bones
- Metaphyseal lesions can extend into diaphysis, esp. in growing bones
- Matrix, periosteal rxn, soft tissue component help differentiate
Diaphysis is a "strong clue" for a few entities, but most lesions cross boundaries. Always correlate clinically and radiologically.
