Lipomas eMedicine

Description: Lipomas are the most common soft tissue tumor. These slow-growing, benign fatty tumors form lobulated soft masses enclosed by a thin fibrous capsule. Although it has been hypothesized that lipomas may rarely undergo sarcomatous change, this event has never been convincingly documented. It is more probable that lipomas are at the benign end of the spectrum of tumors, which, at the malignant end, include liposarcomas (see Pathophysiology). Because more than half of lipomas encountered by clinicians are subcutaneous in location, most of this article will be devoted to that subgroup. Additional information about other locations (eg, intramuscular, retroperitoneal, gastrointestinal) will be included as appropriate.