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Intraosseous Lipoma of the Calcaneus



General Considerations

  • Uncommon, and not as rare as once thought
  • Benign tumor composed of mature, adult fat
  • Adults between 30-60
  • Males slightly more than females
  • Frequent skeletal locations include
    • Proximal femur, intertrochanteric region (34%)
    • Base of neck of calcaneus (8%)
    • Tibia (13%)
    • Ilium (8%)

Clinical Findings

  • Found incidentally 1/3 time
  • Pain
  • Tenderness
  • Swelling 

Milgram's Classification Intraosseous Lipomas

Stage

Description

1

Viable fat without necrosis

2

Viable fat with necrosis and dystrophic calcification

3

Extensive fat necrosis, calcification, cysts

 

Imaging Findings

  • On MRI
    • Fat in lipoma is isointense with subcutaneous fat on T1
    • Low signal on T1 with fat suppression
  • On conventional radiographs
    • Lucent lesion with sclerotic margin
    • Central sclerotic bulls-eye (pathognomonic)
      • Cockade image-resembles the badge or rose worn upon a hat
    • May be associated with mild expansion of long bone

Differential Diagnosis

  • Not to be mistaken for normal areas of lucency in calcaneous and proximal femur
  • Osteonecrosis

Treatment

  • None usually needed if asymptomatic
  • Curettage and bone grafting for symptomatic lesions

Complications

  • Recurrence and malignant transformation is very rare

Prognosis

  • Frequently disappears spontaneously

intraosseous lipoma of calcaneusintraosseous lipoma of calcaneus

Intraosseous Lipoma of the Calcaneus. Lateral conventional radiograph demonstrates a classical well-defined lytic lesion in the calcaneus with a sclerotic margin (black arrow) and a central calcification (white arrow). Sagittal T1 and T1 STIR images demonstrate a fat-containing lesion (black and white arrows).
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Intraosseous lipoma of the calcaneus. Christoph Bertram, Frank Popken and Jürgen Rütt

Archives of Surgery: Volume 386, Number 5 / August, 2001

 

Benign Musculoskeletal Lipomatous Lesions. Mark D. Murphey, MD, John F. Carroll, MD, Donald J. Flemming, CAPT, MC, USN, Thomas L. Pope, MD, Francis H. Gannon, MD and Mark J. Kransdorf, MD. September 2004 RadioGraphics, 24, 1433-1466.