Liposarcoma

January 22, 2026

This page was reviewed under our medical and editorial policy by Lee Cranmer, M.D., Ph.D., professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Cancer Center Duarte.

Liposarcoma is a soft tissue sarcoma (STS) that originates in fatty tissue. Though it’s the most common STS, liposarcoma is relatively uncommon, affecting just 2,000 people each year in the United States, mostly men between the ages of 50 and 60. Children are seldom diagnosed with this type of sarcoma.

What Is Liposarcoma?

Liposarcomas, sometimes called lipomatous tumors, are malignant tumors of fat tissue. They may start anywhere in the body, but most often appear in the arms and legs (particularly the thighs or behind the knee), the abdomen and groin. There are many types of liposarcomas, and they differ in their behavior.

Liposarcoma vs. Lipoma

Lipoma, which also starts in fatty tissue and causes lumps, may resemble liposarcoma, but these diseases differ in various ways. For instance:

• Lipoma is non-cancerous (benign), while liposarcoma is cancerous (malignant)
• Lipoma forms just under the skin, usually in the shoulders, neck, trunk or arms; a liposarcoma malignant tumor forms deeper in the thighs or abdomen
• Lipoma does not spread, but liposarcoma may spread, if untreated
• In some cases, lipomas run in families. People in these families may have more than one lipoma. Again, this does not predispose to development of liposarcomas, which are a form of cancer.

Lipomas are completely different from liposarcomas. It’s important to know that lipomas do not give rise to liposarcomas.

Types of Liposarcoma

There are five main subtypes of liposarcoma.

Well-differentiated liposarcoma: The most common subtype, this is usually slow-growing, painless and found in deeper tissues and the abdomen. They may change into dedifferentiated liposarcomas, as described below. In such cases, patients may have both well-differentiated and dedifferentiated liposarcoma at the same time.

Myxoid liposarcoma: Typically found in the arms and legs, it tends to spread to distant skin, muscle or bone.

Dedifferentiated liposarcoma: This type often arises from an underlying well-differentiated liposarcoma. Unlike well-differentiated liposarcoma, dedifferentiated liposarcoma grows much more quickly and may metastasize (spread) to other parts of the body. It often occurs in the abdomen.

Round cell liposarcoma: This type usually forms in the thigh and involves chromosome changes.

Pleomorphic liposarcoma: The least common subtype, it is most likely to spread or recur after treatment.

The care team performs a biopsy to confirm a diagnosis of liposarcoma and to pinpoint the subtype.

Causes and Risk Factors

Though the specific cause of liposarcoma is still unclear, researchers suggest that genetic changes, or mutations, in fat cells play a role. There are inherited gene mutations, or gene changes inherited from a parent, and acquired gene mutations, which develop at some point during a person's life.

Factors that increase a person’s risk of developing liposarcoma include:

• Previous exposure to radiation
• Personal or family history of cancer
• Exposure to chemicals like vinyl chloride
• Damage to the lymph system

Liposarcoma Symptoms

Initially, liposarcoma does not typically cause symptoms beyond a lump. It may go unnoticed until the tumor has grown large enough to press on neighboring organs. This is especially the case when a liposarcoma develops inside the abdomen. There is a particular area called the “retroperitoneum,” in which this type of cancer commonly develops and is a space shared with the kidneys, liver, and other organs. Symptoms, which are often specific to tumor location, may include:

• A new or growing lump beneath the skin, especially behind the knees or on the thighs
• Pain or swelling, specifically in the belly
• Satiation, or feeling full after eating
• Constipation
• Blood in stool or vomit
• Fatigue or trouble breathing
• Fevers or night sweats
• Weight loss

Tests for Diagnosing

The journey to a liposarcoma diagnosis often involves a combination of tests, including:

• A complete medical history and comprehensive physical exam to look for signs of disease
• A computed tomography (CT) scan, which uses a series of x-rays to see tumor location and size
• Magnetic resonance imaging (MRI), which uses a large magnet and radio waves to create clear images of specific body structures
• A biopsy, which removes a tumor sample for lab examination and testing to confirm a liposarcoma diagnosis. A biopsy specimen may also clarify what specific type of liposarcoma is present and may be useful in identifying specific treatments to use.

Stages

The American Joint Committee on Cancer (AJCC) uses a detailed staging system for soft tissue sarcomas, including liposarcoma, where:

• T stands for main tumor size and location
• N stands for cancer spreading to the lymph nodes
• M stands for metastasis to other parts of the body
• G stands for tumor grade (low- or high-grade), or how the cancer cells look

Within the AJCC system, doctors use these four factors (T, N, M, G) to establish an overall stage for soft tissue sarcomas, classified as 1 to 4. In general, the lower the number, the less the cancer has spread.

The staging system divides sarcomas into grades 1 to 3 to help predict how rapidly they will grow and spread, as detailed below.

Grade 1 or low grade: Cancer cells appear slightly abnormal and slow growing.

Grade 2 or intermediate grade: Cancer cells appear abnormal and grow faster than grade I tumors.

Grade 3 or high grade: Cancer cells appear very abnormal and grow quickly.

Together, cancer grade and stage provide doctors with key information used in personalized treatment planning.

Liposarcoma Treatment

The patient’s care team considers factors like tumor subtype, size and location to develop personalized treatment plans for liposarcoma.

Surgery

As the leading treatment for liposarcoma, surgery is performed to remove the entire tumor and surrounding healthy tissue. It is possible that involved organs, such as the kidney, might also be removed at the time of surgery. It is best if the surgeries are performed by a surgical oncologist experienced in the management of liposarcomas.

Radiation Therapy

Radiation therapy, which uses high-intensity X-rays, may be an option before, during or after surgery to kill cancerous cells and reduce chances of recurrence. The combination of surgery and radiation therapy may prevent tumor recurrence at the surgical site in about 85% to 90% of liposarcoma cases.

The sequencing of radiation therapy and surgery is very important in liposarcomas, especially when they occur within the abdomen or retroperitoneum. Sometimes, it is possible to administer radiation therapy prior to surgery, because sensitive organs within the abdomen are physically moved out of the way by the liposarcoma. After surgery, this may not be possible. Therefore, it is important to consult before initial treatment with surgeons and physicians experienced in the management of liposarcomas.

Chemotherapy

Chemotherapy drugs are often used to destroy cancer cells when liposarcoma has spread, there’s a high risk of recurrence or following surgery to kill any remaining tumors. When someone is first diagnosed with a liposarcoma, chemotherapy may be recommended either before or after the initial surgical treatment. This is yet another reason that it is important to consult with experienced physicians prior to starting treatment.

Who Treats Liposarcoma?

When making treatment decisions, it is important to seek specialized care from experts with experience in soft tissue sarcoma, specifically liposarcoma. The patient’s care team may include:

• Medical oncologists, who treat cancer with chemotherapy and other drugs
• Surgical oncologists, who diagnose and treat cancer with surgery
• Radiation oncologists, who use radiation therapy to destroy cancerous tissue
• Pathologists, who examine tissue samples for diagnostic purposes to help determine a treatment plan
• Radiologists, who utilize imaging tools and interventional techniques to diagnose and treat cancer
• Supportive care providers, who focus on cancer- and treatment-related side effects and symptom management

Liposarcoma Survival Rate

As noted above, the word “liposarcoma” refers to a number of very different diseases. The management and outcome of these conditions is affected by the specific diagnosis, the extent of disease at diagnosis, a patient’s underlying medical conditions, and the experience of the team providing treatment. Thus, specific outcomes and expectations are an important part of the evaluation of any patient being seen for liposarcoma.

In general, the five-year survival rates of certain liposarcoma subtypes are:

• Well-differentiated: 100%
• Myxoid: 88%
• Pleomorphic: 56%
• Round-cell and differentiated: 50%

Liposarcoma patients should always speak with their care team to receive a personalized prognosis evaluation based on the many factors that impact outcome.