Can Lipoma Turn into Cancer?

Lipomas are the most common benign tumor;  they are composed of adipose tissue. Sometimes these soft,  usually mobile  masses can grow in size and become an aesthetic or functional concern.

Malignant transformation of lipomas into liposarcomas  it's extremely rare ( and controversial).

Generally, I  recommend excision to allow for pathologic evaluation (which is the only  way to make a definitive diagnosis) and to  alleviate compressive symptoms it may be causing (as well as for cosmetic purposes).

Best wishes. 

Lipomas do not become or turn into cancer but a cancerous fat tumor called liposarcoma does exist, and can be quite aggressive. A liposarcoma will generally be firmer, more irregular, more adherent and less mobile than a lipoma. Also, liposarcoma is more likely to be painful than a lipoma. It is not always easy to determine if a mass that seems to be a lipoma might actually represent a liposarcoma. That is one reason to excise most lipomas if the diagnosis is in question ands to always send the tissue for a biopsy.