How Liposarcoma Is Diagnosed

Liposarcoma is a type of soft tissue cancer that develops in fat cells. It most commonly forms in the legs, arms, or abdomen. This cancer typically starts in the layer of fat in the tendons, muscles, and/or nerves.

In the beginning stages, the tumor typically appears as a painless, harmless lump under the skin, but as it grows, it may become large enough to put pressure on muscles, nerves, or organs nearby. This may cause additional symptoms.

If liposarcoma is suspected, your healthcare provider will conduct a physical exam, order a biopsy, and schedule imaging tests to reach a diagnosis. This article will review the steps of the diagnostic process.

Nurse prepping patient for biopsy

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Self-Checks/At-Home Testing

There is no at-home test for liposarcoma. In addition, because liposarcoma is so rare, there are no regular screening tests available.

If you notice an unusual lump on your body that doesn't go away or is growing, or if you are experiencing other unusual symptoms, such as extreme fatigue, stomach pain, or blood in your stool, schedule an appointment with your healthcare provider.

Physical Examination

If liposarcoma is suspected, your healthcare provider will first conduct a physical exam. During this exam, a healthcare professional will ask you questions about your medical history and your family medical history, including whether anyone else in your family has had cancer.

In addition, they will ask detailed questions about any symptoms you are experiencing. The healthcare professional will also give a thorough physical exam, looking closely at the lump and feeling it for abnormalities. If there is an area for concern, they will order more tests.

Labs and Tests

The most important step in diagnosing liposarcoma is taking a biopsy. This is a procedure where a doctor uses a hollow needle to remove a sample of tissue from the lump. Depending on the location of the tumor, the biopsy can usually be done under localized anesthesia (where just the affected area is numbed).

Once the tumor sample has been retrieved, it is then sent to a lab. A pathologist (a doctor specialized in diagnosing disease) will examine the tissue under a microscope to confirm whether it contains cancerous cells. If it does, the sample will also be tested to determine the type of liposarcoma to help determine the best course of treatment.

Your healthcare provider will also likely order blood tests, including a complete blood count and comprehensive metabolic panel, to gauge your overall health, which is an important factor in deciding on how to proceed with treatment.

 Imaging

Imaging tests are also conducted when diagnosing liposarcoma to help locate tumors and to determine if and where the cancer has spread. Tests that may be ordered include the following:

  • Ultrasound: This test uses sound waves to create digital images of body tissues, like the organs.
  • X-ray: This is a lower-cost imaging test that may be used to detect cancer in different areas of the body including the organs, stomach, kidneys, and bones.
  • Magnetic resonance imaging (MRI): An MRI shows cross-section photos of the inside of your body. This test can get a clear image of soft tissue that is typically difficult to see in other imaging tests.
  • Computed tomography (CT) scan: A computer compiles multiple X-ray images into a three-dimensional image that can reveal the tumor's shape, size, and location and show a clear picture of the surrounding soft tissues, organs, and bones. This test can also be useful in monitoring how a patient is responding to treatment and checking to see if cancer has returned after treatment for follow-up checkups. 

Classifying Different Types of Liposarcoma

Once a pathologist has confirmed the tumor is cancerous, they look more closely at the cancer cells and do tests to determine the type of liposarcoma, which helps indicate how fast the cancer is growing. The five subtypes of liposarcoma include:

  • Well-differentiated: This is the most common type of liposarcoma. It is characterized by cells that grow slowly and are not known to spread. They also resemble a normal fat cell.
  • Myxoid: This type of liposarcoma often develops in the legs and arms and is known to spread to unusual areas, including the bones, muscles, or distant skin.
  • Dedifferentiated: These slow-growing cancer cells tend to start in the abdomen, but they can also form in the chest and extremities.
  • Round cell: This cancer most commonly develops in the thighs. It may cause changes to the chromosomes (genetically material) in the cells.
  • Pleomorphic: This is the rarest type of liposarcoma, but it is fast-growing with higher rates of recurrence and poorer outcomes.

Differential Diagnosis

Other conditions can present similarly to liposarcoma, and your healthcare team will rule them out before reaching a diagnosis. Other conditions they may look at include a benign (non-cancerous) tumor called a lipoma and other types of soft tissue tumors, such as undifferentiated pleomorphic sarcoma (a tumor that most often forms in the leg), lipomatous hemangiopericytoma (a tumor that forms deep in soft tissue), and gastrointestinal stromal tumor (a tumor that forms in the stomach).

Summary

Liposarcoma is cancer that forms in fat cells. It usually first appears as a painless lump under the skin. Diagnosing liposarcoma typically involves a physical exam, a biopsy (a procedure to extract a tissue sample from the tumor to be examined and tested for cancer cells in a lab), blood tests, and imaging tests including ultrasound, X-ray, MRI, or a CT scan.

 A Word From Verywell

Going through testing for cancer can be terrifying and stressful, but it's important not to jump to conclusions. Your healthcare team is available to answer any questions and field your concerns as you go through the process. They will do everything in their power to get an accurate diagnosis and formulate a treatment plan with your best outcome in mind.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cleveland Clinic. Liposarcoma.

  2. Johns Hopkins Medicine. Liposarcoma

  3. National Organization for Rare Diseases. Liposarcoma.