Liposclerosing myxofibrous tumor

Last revised by Dr Bahman Rasuli on 11 Apr 2021

Liposclerosing myxofibrous tumors (LSMFT), also known as polymorphic fibro-osseous lesions of bone, are rare benign fibro-osseous lesions that have a predilection for the intertrochanteric region of the femur.

It is slightly more common in males with mean age of 30-40 years. It can be discovered incidentally but most patients have vague longstanding pain. About 10% of patients present acutely with pathologic fracture.

The tumor comprises of the wide mixture of tissues of lipomatous, fibroxanthomatous, myxomatous, and myxofibromatous components inclusive. 

Tends to have a striking predilection for the intertrochanteric region of the femur (80-90%) 1-3.

  • geographic lucent lesion usually centered in intertrochanteric region of the proximal femur
  • sclerotic margin
  • mildly expansile
  • multilocular
  • matrix calcification in ~70% of cases
  • fat density component

Despite its name, distinct fatty components are not seen

  • T1: relatively homogeneous and isointense to skeletal muscle
  • T2: moderately heterogeneous with areas of high signal due to myxoid component

Scintigraphy can show mild focal uptake with Tc-99m pertechnetate 1.

  • incidentally detected asymptomatic lesions: no treatment or intervention 1
  • symptomatic lesions: are commonly managed with bone curettage, bone grafting, and fixation 1
  • pathological fracture: uncommon ~10%; proximal femoral lesions may require arthroplasty 1
  • malignant transformation: rare but documented 10-15%; transformation into osteosarcoma is the most common

Due to this potential malignant transformation, lesions need follow-up imaging preferably by MRI. Symptomatic lesions or those with interval change require surgical resection 3.

On radiographs consider:

  • fibrous dysplasia: it is challenging to differentiate between both by imaging. Fibrous dysplasia may show less sclerosis by radiography, more uptake by scintigraphy and intermediate or low signal intensity by fluid sensitive MRI sequences 1
  • intraosseous lipoma: LSMFT does not usually show macroscopic fat on CT or MRI as lipomatous component is usually too small and mixed with other more prominent myxofibrous or fibro-osseous tissue
  • aneurysmal bone cyst (ABC): usually more expansile 

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Cases and figures

  • Case 1: in right femur
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  •  Case 2
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  • Case 3
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  • Case 4
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  • Case 5
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