The radiograph answers it: the zone of transition, the periosteal reaction and cortical destruction tell you how fast the lesion is growing. Age and location then narrow the differential; MRI stages it.
Orient first
- A narrow zone of transition with a sclerotic rim is slow-growing; a wide zone (permeative or moth-eaten) is aggressive.
- Solid, thick periosteal reaction means slow; interrupted, lamellated (onion-skin), sunburst or Codman triangle means aggressive.
- Age is the strongest single discriminator: in a patient over about 40, a lytic lesion is metastasis or myeloma until proven otherwise.
Acquire the study
- AP and lateral of the whole bone including both joints.
The manoeuvre
- Location: epiphysis, metaphysis or diaphysis; central, eccentric or cortical.
- Zone of transition: sclerotic rim, narrow without rim, wide, moth-eaten, permeative (Lodwick grade).
- Periosteal reaction: none, solid, lamellated, spiculated, Codman triangle.
- Matrix: chondroid (rings and arcs), osteoid (cloud-like), ground glass (fibrous).
- Cortex: endosteal scalloping, expansion, breach; soft-tissue mass.
What confirms it
- A statement of aggressive or non-aggressive, from the named features.
What licenses you to exclude it
- A classic "don't touch" lesion (non-ossifying fibroma, bone island, enchondroma without worrying features) needs no biopsy.
The classic misread
- Calling a lesion benign on the radiograph when a soft-tissue mass is present.