Lucent/lytic bone lesion - differential diagnosis (mnemonic)

Last revised by Dr Daniel J Bell on 15 Mar 2021

Mnemonics for the differential diagnosis of lucent/lytic bone lesions include:

  • FEGNOMASHIC
  • FOG MACHINES

They are anagrams of each other and therefore include the same components. They are by no means exhaustive lists, but are a good start for remembering a differential for a lucent/lytic bone lesion and will suffice for >95% of the time 1.

Mnemonics

FEGNOMASHIC
FOG MACHINES
  • F: fibrous dysplasia (FD) or fibrous cortical defect (FCD)
  • O: osteoblastoma
  • G: giant cell tumor (GCT) or geode
  • M: metastasis(es)/myeloma
  • A: aneurysmal bone cyst (ABC)
  • C: chondroblastoma or chondromyxoid fibroma
  • H: hyperparathyroidism (brown tumor)
  • I: infection (osteomyelitis) or infarction (bone infarction)
  • N: non-ossifying fibroma (NOF)
  • E: enchondroma or eosinophilic granuloma (EG)
  • S: simple (unicameral) bone cyst

These lists are not exhaustive (e.g. intraosseous lipoma is omitted)

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Cases and figures

  • Case 1: Metastasis - RCC
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  • Case 2: Multiple myeloma - skeletal survey
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  • Case 3: Multiple myeloma - skeletal survey
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  • Case 4: Aneurysmal bone cyst
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  • Case 5: Giant cell tumor
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  • Case 6: Giant cell tumor
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  • Case 7: Enchondroma
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  • Case 8: Aneurysmal bone cyst (ABC) - tibia
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  • Case 9: Osteoblastoma
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