lumbar > cervical spine (22%); involvement of vertebral body (40-90%); may involve two contiguous vertebrae (25%).(b) long bones; eccentric in metaphysis of femur, tibia, humerus, fibula; pelvis aggressive expansile ballooning lesion of "soap-bubble" pattern + thin internal trabeculations rapid progression within 6 weeks to 3 months.Sclerotic inner portion almost invisible thin cortex (CT shows integrity) tumor respects epiphyseal plate no periosteal reaction (except when fractured).">