Lipoma vs well-differentiated liposarcoma
There a number of features that can help distinguish between lipoma and well-differentiated liposarcoma. This article relates to superficial well-differentiated liposarcomas that typically occur in the extremities, also known as atypical lipomatous tumors, and not retroperitoneal liposarcoma.
Epidemiology
Demographic factors that favor well-differentiated liposarcoma are age >60 years and male sex .
Radiographic features
MRI
MRI can have 100% sensitivity for the diagnosis of well-differentiated liposarcomas, however, has a low positive predictive value due to overlap of imaging features with benign lipoma variants . Features that favor well-differentiated liposarcoma :
- size >10 cm
- percentage fat <75%
- thick or nodular (>2 mm) septa
- nodular/globular areas
- prominent high T2 signal foci
- prominent enhancement
- associated non-adipose mass
- lower limb location
- intramuscular location
Features that favor lipoma :
- size <10 cm
- percentage fat >75%
- no or few thin (<2 mm) septa
- no or minimal enhancement
- no or minimal high T2 signal foci
- subcutaneous location