Liposarcoma

We categorize liposarcoma based on where tumors form and how aggressively they act.

Liposarcoma types include:

• Well-differentiated liposarcoma: The most common liposarcoma, these tumors feature clearly defined cells that look a lot like normal cells. These cancers rarely spread but do often return after surgical treatment. They’re found in the retroperitoneum (back half of the belly) and the esophagus. In the arms and legs, a similar but benign tumor called an atypical lipoma can develop. In 2 percent of cases, these lipomas can turn into liposarcoma.
• Myxoid liposarcoma: Among liposarcomas, these tumors are also relatively common, especially in adults ages 35 to 55. Myxoid liposarcoma is found most often in the thighs. It can also form in the chest wall, pelvis, arms, and other parts of the legs.
• Round cell liposarcoma: Named after the shape of its cells, round cell liposarcoma is the more aggressive version of myxoid liposarcoma and occurs in the same locations. It can spread to other areas of the body, including the lungs, abdomen, and spine.
• Dedifferentiated liposarcoma: This less common form of liposarcoma is found in the belly, arms, and legs. Its cells appear dedifferentiated, meaning that they are in a less mature form. Dedifferentiated liposarcoma can act more aggressively at times. For example, it returns more often after treatment when found in the belly. Still, dedifferentiated liposarcoma spreads to other areas of the body less commonly than other aggressive liposarcomas.
• Pleomorphic liposarcoma: The rarest liposarcoma, these tumors have cells that take on a range of shapes and sizes. Found mainly in the arms and legs, these sarcomas are particularly aggressive, with the ability to spread to distant locations, particularly the lungs.

When they first form, liposarcomas often don’t cause any symptoms and frequently go unnoticed. They may eventually grow large enough to push other tissue aside and cause symptoms. The liposarcoma symptoms you may experience depend on the size of the tumor and where it forms:

• Abdominal symptoms: You may experience constipation, feeling full sooner than usual when eating, nausea, pain, swelling, unintended weight loss, or vomiting.
• Arm or leg symptoms: You will most commonly notice a growing lump but generally no pain or physical limitations.
• Esophageal symptoms: You may experience trouble swallowing or unintended weight loss.

The exact causes of liposarcoma aren’t currently known. Some factors, however, may increase your risk of developing one:

• Chemical exposure: Some evidence suggests that exposure to workplace chemicals such as vinyl chloride can cause a liposarcoma to eventually form.
• Family genetics: Genetic changes inherited from parents can cause syndromes that increase the risk for a range of health conditions, including sarcomas and other cancers. Both hereditary retinoblastoma—a cause of eye cancer—and Li–Fraumeni syndrome (LFS) have ties to liposarcoma.
• Lipomas: Most benign lipomas don’t turn cancerous. In 2 percent of cases, a specific kind of tumor called an atypical lipoma may become a liposarcoma.
• Previous radiation therapy: Receiving radiation therapy can cause a liposarcoma to form years later.

If a liposarcoma is suspected, doctors must distinguish the tumor from other possible soft tissue cancers, including gastrointestinal stromal tumor (GIST), leiomyosarcoma, and undifferentiated pleomorphic sarcoma (UPS).

To evaluate a suspicious mass, we start with an exam of the affected area. We will also talk to you to understand your symptoms. Scans such as computed tomography (CT) and magnetic resonance imaging (MRI) can provide more information on the tumor and surrounding area. Lipomas have a very distinctive appearance in imaging, as do many well-differentiated liposarcomas.

Scans can also look for the spread of cancer. For the esophagus, we may use upper gastrointestinal (GI) endoscopy to look for cancer.

If we suspect cancer, we will often perform an image-guided needle biopsy. This procedure takes a small sample of tumor tissue, for study under a microscope and evaluation with lab tests.

If cancer is confirmed, the exam, scans, and biopsy results help us determine its stage and make treatment recommendations.

Liposarcoma treatments depend on the type of tumor diagnosed, its location, and its stage.

At Penn, liposarcoma treatment typically focuses on surgically removing the tumor. As with sarcoma surgery for other tumor types, the best results typically come from taking out the liposarcoma in one piece, along with a surrounding area of healthy tissue. We have extensive experience with this method.

In the retroperitoneum, operations may require taking out the colon, kidneys, spleen, or pancreas in one piece. In the arms and legs, our surgeons use specialized techniques to preserve limb function in most cases. In the esophagus, our surgeons usually replace some or all of the organ, using a minimally invasive approach whenever possible.

To reduce the risk of cancer recurring (returning), we may recommend adding radiation therapy. Myxoid liposarcomas are particularly sensitive to radiation. More aggressive round cell tumors may also respond to chemotherapy.

Additional therapies for cancer that spreads or comes back depend on tumor type. Immunotherapy—drugs that harness the immune system—can treat some dedifferentiated liposarcomas, for example. Given the need for further options, sarcoma clinical trials continue to look for promising new approaches.