Imaging

Pathology

Clinical Issues

Diagnostic Checklist

Synonyms

• Fatty tumor

Definitions

• Benign
  • Lipoma: Benign soft tissue tumor composed of mature adipose tissue
  • Angiolipoma: Lipoma in which small capillary-sized vessels containing microthrombi transverse tumor
  • Lipomatosis: Diffuse infiltrative overgrowth of mature adipose tissue, completely or partially encapsulated
  • Lipomatosis of nerve: Median > > > other nerves ± localized mesenchymal overgrowth
  • Spindle cell lipoma: Mixture of fat and spindle cells; more common in head and neck subcutaneous tissues and adult males
  • Lipoblastoma: Admixture of mature and immature adipocytes; more common in extremities and children < 3 years old
  • Hibernoma: Tumor of brown (thermogenic) fat similar to that found in hibernating animals; > subcutaneous tissues of adults, especially lower neck, mediastinum, and upper dorsal region
  • Chondroid lipoma: Adult females, shoulder or pelvic girdle, may calcify
  • Myolipoma: Benign tumor exhibiting features of mature smooth muscles and mature adipose tissue
  • Lipoma arborescens: Subsynovial fatty proliferation, knee > > > ankle or hip; may occur in tendon sheath
• Intermediate
  • Well-differentiated liposarcoma: Slow-growing, usually deep-seated tumor that does not metastasize but is prone to local recurrence; dedifferentiation risk: 6%
• Malignant
  • Dedifferentiated liposarcoma: Deep-seated and large with significant (> 25%) nonfatty component; malignant potential
  • Myxoid liposarcoma: Myxoid tumor either low grade (< 5% round cell component) or high grade (> 5% round cell component)
  • Pleomorphic liposarcoma: Large mass with myxoid, necrotic, fatty, and hemorrhagic components

General Features

Radiographic Findings

CT Findings

MR Findings

Ultrasonographic Findings

Imaging Recommendations

General Features

Gross Pathologic & Surgical Features

Presentation

Demographics

Natural History & Prognosis

Treatment

Consider

Image Interpretation Pearls