Age / Sex : 23 / M

Chief complaint: Right hip pain (onset: 2 years ago/acute aggravation 2 weeks ago))

What is your impression?
Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy of Suk-Joo Hong, Korea Univ. Guro Hospital  

Discussion

Answer: LIPOSCLEROSING MYXOFIBROUS TUMOR (LSMFT)

Findings:

• Plain radiographs: about 6.5cm sized multi-lobulated osteolytic lesion along right femoral head and neck


• Outside CT, MR: multi-lobulating osteolytic mass with thin sclerotic rim is seen in right femoral head and neck, epimetaphysis, eccentrically, which shows fat component, slight trabeculations, and focal calcification. The mass shows T2 heterogeneous high, T1 iso to high SI, and peripheral enhancement. There is BM edema around the mass and synovitis in the right hip joint.

Differential Diagnosis:

1. Intraosseous lipoma, 2. Fibrous dysplasia

Diagnosis:  

LIPOSCLEROSING MYXOFIBROUS TUMOR (LSMFT)

Discussion: LIPOSCLEROSING MYXOFIBROUS TUMOR (LSMFT)

• Benign fibro-osseous tumor of the bone


• Complex mixture of histologic elements
  
  
  
  • Include lipoma, fibroxanthoma, myxoma, myxofibroma, fibrous dysplasia–like features, cyst formation, fat necrosis, ischemic ossification, and, rarely, cartilage.
  
  
  
  


• May a variant of fibrous dysplasia


• Femur (85%)
  
  
  
  • Intertrochanteric region(90%)
  
  
  
  


• Radiography
  
  
  
  • Well-defined lytic defect with a densly sclerotic rim
    
    
    
    • Reflecting an indolent pattern of growth
    
    
    
    
  
  
  • Normal or slightly expanded cortical contour
  
  
  • Occasionally a mineralized matrix is present
  
  
  
  


• MRI
  
  
  
  • Non-specific with high SI on T2WI or fluid-sensitive MRI due to myxoid content
  
  
  
  


• Bone scintigraphy
  
  
  
  • mild to moderate uptake
  
  
  • D/Dx intense uptake in fibrous dysplasia
  
  
  
  


• Lipomatous tissue is typically not identified on CT or MR images
  
  
  
  • reflects the modulation and intermixture of fat with myxofibrous or fibroosseous tissue
  
  
  
  




• D/Dx
  
  
  
  • Intraosseous lipoma: Identifying fat
  
  
  • Fibrous dysplasia: Less sclerosis and greater radionuclide accumulation on bone scintigrams / signal intensity : variable, but intermediate or decreased signal intensity often seen on fluid-sensitive MRI
  
  
  
  

References:

1. Mark J. Kransdorf, MD, et al. Liposclerosing myxofibrous tumor: A radiologic-pathologic-distinct fibro-osseous lesion of bone with a marked predilection for the intertrochanteric region of the femur. Radiology 1999; 212:693-698


2. Mark D. Murphey, MD, et al. From the archives of the AFIP: Benign musculoskeletal lipomatous lesions. Radiographics 2004;24:1433-1466