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Lytic bone lesion

MSKRadiograph / CT / MRI

A radiolucent bone lesion. Patient age is the single most useful discriminator; zone of transition and periosteal reaction indicate aggressiveness.

Differential

Metastasis / myeloma

common
  • Age >40 y, multiple lesions
  • Permeative destruction; myeloma "punched-out" without sclerotic rim
  • Known primary or paraproteinaemia

Simple (unicameral) bone cyst

common
  • Central, geographic, mildly expansile in a child
  • Metaphysis of proximal humerus/femur; fallen-fragment sign

Giant cell tumour

less-common
  • Eccentric, subarticular extending to the articular surface
  • Closed physis (20–40 y); narrow zone of transition, no rim

Aneurysmal bone cyst

less-common
  • Expansile, multiple fluid–fluid levels on MRI
  • Eccentric metaphyseal; <20 y

Fibrous dysplasia

less-common
  • Ground-glass matrix with a sclerotic ("rind") margin
  • Diaphyseal/metadiaphyseal; no periosteal reaction

Chondrosarcoma

rare
  • Chondroid rings-and-arcs matrix with endosteal scalloping
  • Older adult; deep pain, cortical breach

Key discriminators

  • Patient age (single best discriminator)
  • Zone of transition (narrow benign vs wide/permeative aggressive)
  • Matrix (chondroid rings-and-arcs vs ground-glass)
  • Location within bone (epiphysis/metaphysis/diaphysis; central vs eccentric)
  • Periosteal reaction and cortical integrity

Work-up / next steps

  1. 1.Radiograph first to assess matrix, margin and periosteal reaction
  2. 2.MRI for marrow extent and soft-tissue component
  3. 3.Skeletal survey / whole-body imaging and myeloma screen if multiple
  4. 4.Biopsy at a bone-tumour centre for aggressive lesions

References

  • Radiopaedia: Lytic bone lesion.
  • Miller TT. Bone tumors and tumor-like conditions. Radiology.

Educational clinical decision support only. This differential does not make a diagnosis, is not a medical device, and must never substitute for interpretation by a qualified radiologist correlated with the full clinical picture and prior imaging.