Tumor biology
Rare, aggressive, malignant tumor
Gender
M:F = 2:1
Radiographic appearance
Confusing radiographic picture, with aggressive and nonaggressive features possible
Generally a cystic/lytic lesion, although indistinct margins may be seen
Site
Principally involves femur, tibia, and humerus at metaphyseal level
Tumor effect on bone
Most common pattern is lytic and expansile; may have a moth-eaten or permeative pattern (rare)
Periosteal reaction
May or may not be present
Soft tissue mass
Generally present, with hemorrhagic tumor extending into soft tissues
Differential diagnosis
Similar for all lytic expansile metaphyseal lesions
- Aneurysmal bone cyst
- Giant cell tumor
- Brown tumor
- Osteoblastoma
Pathology
Characterized by cystic, blood-filled channels lined by malignant tumor cells
Treatment
- Similar to conventional osteosarcoma
- Lesion responsive to chemotherapy
- Previous reports of particularly bad prognosis for this variant of osteosarcoma probably innaccurate