Can Lipoma Turn into Cancer?

Lipomas can not turn into cancer, however liposarcomas and other rare fatty tumors could potentially be present.  Lipomas are best removed by direct excision rather than liposuction.  Best Anil Shah

A benign lipoma would not turn into a malignant liposarcoma, but without taking a biopsy or removing the lesion, it is impossible to know for certain whether a particular mass is a benign lipoma or a very rare liposarcoma. A diagnosis made without removing some tissue for pathologic analysis is simply an educated guess. In most cases, excision of the lipoma (or at the very least a biopsy) is recommended.
All the best,

Lipomas can mimic cancer and vice-versa. It is always advisable to remove lipomas before they enlarge.  A pathologic specimen is sent to evaluate the tumor with a microscope. Raffy Karamanoukian MD FACS

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.

A lipoma by definition is NOT a cancer.  A lipoma will no turn into a cancer.  The tricky part is knowing, in fact, that you are dealing with a lipoma and not another type of tumor.  Other tumors such as liposarcomas or sarcomas may appear quite similar to a lipoma.  A formal evaluation may be very important in understanding your risks as it relates to cancer.