A new or growing lump under your skin can be a symptom of liposarcoma, a type of cancer that starts in fat cells. Although the lump may be nothing serious, it's a good idea to get it checked out by your doctor.
If you do have liposarcoma, the earlier you get a diagnosis, the sooner you can start treatment.
Getting an Exam
At your visit, your doctor will first ask about your symptoms. Then you'll go over your health history.
They might ask if you have any family members with diseases such as neurofibromatosis, which can raise your chances of getting liposarcoma.
During the exam, your doctor will look at and touch the lump. A growth under your skin that's bigger than 2 inches may be a sign of liposarcoma.
The next step is to get imaging tests, which look for a tumor inside your body. They can show your doctor where the cancer is and how far it has spread.
Some tests you may get are:
X-ray. It uses radiation in low doses to make images of the inside of your body. It can reveal tumors and other growths.
CT scan. It's a powerful X-ray that makes detailed, three-dimensional pictures of structures in your body. A chest CT scan can show whether the cancer has spread to your lungs.
MRI. This test uses powerful magnets and radio waves to make pictures inside your body that help tell the difference between cancer and a noncancerous growth.
PET scan. For this test, a technician injects a small amount of radioactive material into your body. This material acts like a "tracer" by revealing cancer cells on the images.
Ultrasound. It uses sound waves to create pictures of organs and tissues.
A radiologist will review the scans and let your doctor know if the growths look like cancer. For further testing and treatment, you'll see an oncologist -- a specialist who treats liposarcoma and other cancers.
A biopsy is the only way to know for sure that you have liposarcoma. During this test, your doctor removes a small piece of tissue from the lump. This can be done in one of two ways:
Needle biopsy. Your doctor puts a needle into the growth and pulls out a piece of tissue. Because liposarcoma is often deep inside your body, an ultrasound can help your doctor place the needle in the right place.
Surgical biopsy. Your doctor makes a cut in your skin and removes a small piece of the tumor. The sample goes to a lab, where a technician checks the cells under a microscope to see if they look like cancer.
The sample may go through more advanced tests, including genetic tests, to help your doctor figure out your treatment options. Genetic tests look for changes to single genes, chromosomes, or short pieces of DNA in the cancer.
Your doctor will use the results of these tests to confirm whether you have liposarcoma and where it is in your body. They'll give your cancer a grade and stage based on how different it looks from normal cells, how fast it grows, and whether it has spread.
For instance, your doctor may tell you that your liposarcoma is one of these grades:
Low-grade. The cancer looks a lot like normal cells and grows slowly.
Intermediate-grade. The cancer looks more abnormal than other cells and grows a little bit faster.
High-grade. The cancer grows quickly and is more likely to spread.
Liposarcoma has four stages:
Stage I. A small cancer that is low grade and hasn't spread to other parts of your body.
Stage II. It's often larger and faster growing than stage II, but it has not spread.
Stage III. A high-grade cancer that hasn't spread.
Stage IV. The cancer can be any grade or size, but it has spread to other areas of your body.
Based on the grade and stage of your cancer, your doctor will tell you what to expect and create a personalized treatment plan. Ask your doctor to explain your diagnosis to you and let you know what it means for your treatment.
American Cancer Society: "Risk Factors for Soft Tissue Sarcomas," "Soft Tissue Sarcoma Stages,"
Lancet Oncology: "Clinical effect of molecular methods in sarcoma diagnosis (GENSARC): a prospective, multicentre, observational study."
Mayo Clinic: "Liposarcoma: Diagnosis & Treatment."
Medscape: "Liposarcoma," "Liposarcoma Workup."
National Organization for Rare Disorders: "Liposarcoma."
The Liddy Shriver Sarcoma Initiative: "The Importance of Biopsy in Sarcoma Diagnosis," "What is liposarcoma?"
University of Rochester Medical Center: "Liposarcoma."