Liposarcoma
A rare cancer that develops in fat cells
Quick Facts
- Type: Soft tissue sarcoma (cancer of fat)
- Common sites: Thigh, behind the abdomen, limbs
- Common sign: A deep, painless, growing lump
- Main treatment: Surgery, sometimes with radiation
Overview
Liposarcoma is a rare type of cancer that develops in fat (adipose) cells. It belongs to a group of cancers called soft tissue sarcomas, which arise in the connective tissues of the body. Despite forming in fat tissue, it is unrelated to common, harmless fatty lumps called lipomas.
Liposarcoma most often appears as a deep mass in the thigh or other limbs, or in the area behind the abdominal cavity (the retroperitoneum). There are several subtypes that range from slow-growing and less aggressive to fast-growing and more dangerous, which affects treatment and outlook. Treatment is usually led by a specialist sarcoma team.
Symptoms
Symptoms depend on where the tumor is and how large it has grown. Because liposarcomas often grow deep within tissue, they may become large before causing problems. Possible signs include:
- A deep, firm lump or swelling, often in the thigh or limb, that grows over time
- A lump that is usually painless at first
- Abdominal swelling, fullness, or discomfort if the tumor is behind the abdomen
- Pressure on nearby nerves, blood vessels, or organs, causing pain, numbness, or changes in bowel or bladder function
- Loss of appetite or a feeling of fullness with large abdominal tumors
Any lump that is deep, larger than a few centimeters, growing, or causing symptoms should be evaluated.
Causes
The exact cause of liposarcoma is not known. Like many cancers, it develops when changes (mutations) occur in the genes of fat cells, causing them to grow uncontrollably and form a tumor. These genetic changes are usually acquired during life rather than inherited.
Liposarcoma does not develop from ordinary lipomas, and there is no evidence that diet or everyday lifestyle causes it. Most cases occur without an identifiable reason.
Risk Factors
- Adulthood, with many cases in middle-aged and older adults
- Previous radiation therapy to an area, which slightly increases sarcoma risk
- Certain rare inherited cancer syndromes
- Exposure to some industrial chemicals in rare cases
For most people, no specific risk factor is identified.
Diagnosis
Diagnosis involves imaging and a tissue sample:
- Imaging: MRI is often used for limb tumors and CT for abdominal tumors to show the size, location, and relationship to nearby structures.
- Biopsy: A sample of the tumor is taken and examined to confirm the diagnosis and determine the subtype and grade.
- Staging tests: Additional scans may check whether the cancer has spread, which guides treatment.
Diagnosis and care are best handled by a specialized sarcoma center because of the variety of subtypes.
Treatment
Treatment is tailored to the tumor's location, subtype, grade, and stage.
- Surgery: The main treatment is surgical removal of the tumor with a margin of healthy tissue. Complete removal offers the best chance of cure.
- Radiation therapy: Often used before or after surgery, particularly for limb tumors, to reduce the risk of the cancer returning.
- Chemotherapy: May be used for higher-grade tumors, certain subtypes, or cancer that has spread.
- Specialist follow-up: Regular monitoring is important because liposarcomas can recur, especially those behind the abdomen.
The outlook varies widely by subtype and grade; lower-grade tumors that are fully removed often have a favorable outcome.
Prevention
Because the cause is usually unknown, there is no proven way to prevent liposarcoma. The most useful step is early detection:
- Have any deep, firm, or growing lump checked by a doctor, especially if larger than a few centimeters
- Do not assume a new lump is a harmless fatty lump without evaluation
- Report new abdominal swelling or persistent fullness
- Attend follow-up appointments if you have had a sarcoma before
When to See a Doctor
See a doctor if you notice a lump that is deep, firm, larger than a few centimeters, growing, or causing pain or other symptoms. While most lumps are harmless, these features warrant evaluation to rule out a sarcoma.
Also seek care for unexplained abdominal swelling, persistent fullness, or new pressure symptoms such as numbness or changes in bowel or bladder function, which can occur with tumors behind the abdomen.
Frequently Asked Questions
Is a fatty lump the same as liposarcoma?
No. Most fatty lumps are lipomas, which are common and harmless. Liposarcoma is a rare cancer that does not develop from lipomas. However, a deep, firm, or growing lump should be checked to tell the two apart.
Where does liposarcoma usually appear?
It most often forms a deep mass in the thigh or other limbs, or in the area behind the abdominal cavity. Limb tumors may be felt as a lump, while abdominal tumors can cause swelling or fullness.
Is liposarcoma curable?
Many liposarcomas, especially lower-grade tumors that are completely removed by surgery, have a favorable outlook. The outcome depends on the subtype, grade, size, location, and whether it has spread.
What causes liposarcoma?
It develops from genetic changes in fat cells that are usually acquired during life rather than inherited. Most cases have no identifiable cause, and it is not caused by diet or ordinary fatty lumps.
How is it treated?
The main treatment is surgical removal, often combined with radiation therapy, especially for limb tumors. Chemotherapy may be used for higher-grade or spread disease. Care is best provided by a specialized sarcoma team.
References
- National Cancer Institute (NCI). Soft Tissue Sarcoma Treatment.
- American Cancer Society. Soft Tissue Sarcoma.
- MedlinePlus, U.S. National Library of Medicine. Soft tissue sarcoma.
- National Organization for Rare Disorders (NORD). Liposarcoma.