Most people tend to be distressed upon finding unusual growth anywhere in the body, particularly a lump. Lipomas are fatty lumps that grow under the skin. A true lipoma is benign, that means it does not spread and is not life threatening. A true lipoma will not turn into a cancerous tumor. Benign tumors or masses do not turn into cancers. However, occasionally, a mass or lump which is presumed to be a benign tumor before biopsy or removal and later pathologic examination, turns out to be a malignant tumor (cancer).

Lipomas can be confused with liposarcomas. For that reason, a tissue sample of the lipoma, which is collected by biopsy, needs to be examined under a microscope by a pathologist to identify if it is indeed a lipoma or a liposarcoma.

Liposarcoma

Liposarcoma is a soft tissue cancer originated from fat cells. While lipomas are very common, liposarcomas are rare, but they do occur.  Liposarcoma can occur in almost any part of the body, but more than half of liposarcoma cases involve the thigh. The patient may not notice for a long time because liposarcomas are normally painless.

How is a liposarcoma diagnosed

• Physical examination. Large (bigger than 5cm) and deep-seated lumps are considered suspicious.
• Imaging tests. Imaging tests can show if cancer has spread. Benign and cancerous tumors may look different on imaging tests, such as an x-ray. Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI) are also often used.

It is extremely hard to tell the difference between a liposarcoma and a lipoma based solely on physical examination or any imaging study (CT scan or MRI). A biopsy will be ordered by your doctor if there is any doubt.

• Biopsy. Because soft tissue sarcoma is not common, an expert pathologist should review the tissue sample to properly diagnose a sarcoma. Properly diagnosing a sarcoma requires special tests, and it is best if a specialist who sees this type of cancer every day does this. The result of the biopsy and imaging studies help doctors recognize the stage of the disease, that can be used to create a treatment plan.

Liposarcoma usually affects adults between 40 and 60 years old. The cause of liposarcoma is not well understood yet by scientists, but it is also not known to develop from benign lipomas, which are harmless lumps of fat.

However, you should be cautious if the lipoma grows rapidly in size and causes troubling symptoms. It is recommended to remove all masses that are large, symptomatic or growing to confirm the masses are benign.

Excision surgery is the best choice for lipoma removal because it allows for pathological examination. And it is better to have it done when the lipoma is still small to minimize scarring. On the other hand, lipoma removal with liposuction is not preferred because it can’t provide a tissue sample to be further examined under a microscope to know definitively if it is not cancerous.

Sampling error may play a part in the whole phenomenon of a lipoma being cancerous. Some studies argue that a lipoma was actually a well-differentiated liposarcoma all along and was just not aggressive.

Well-differentiated liposarcoma, or atypical lipoma, is in the middle spectrum of benign lipoma and high-grade liposarcoma. High-grade liposarcoma is more aggressive, it has a higher risk of spreading than low-grade liposarcoma. Well-differentiated liposarcoma tend not to spread, it is not life threatening but they can grow back. It remains a gray area regarding the state of well-differentiated liposarcoma being completely benign or cancerous.

Liposarcoma treatment

Surgery

Surgery is the treatment for primary liposarcomas that have not yet spread to other organs. In most cases, a surgeon will remove the tumor, along with some of the healthy tissues around the tumor, with an intention to leave the area free of disease and preventing the tumor from returning.

With well-differentiated liposarcoma, a patient will be asked to come back for a periodic check-up, so a doctor can monitor and see if there is any recurrence of the tumor.

Radiation therapy

Radiation therapy can be used before, during, or after the surgery. The purpose of radiation therapy is to kill and reduce the chance of the tumor returning in the same location.

The combination of surgery and radiation therapy has been shown to prevent recurrence at the surgical site in about 85% of liposarcoma cases.

Chemotherapy

Chemotherapy may be recommended in certain situations where patients are at high risk of recurrence or already have a widespread disease.

Conclusion

The word cancer is universally feared. When it comes to lumping found in the body, it is important to really be sure of what it actually is. Please consult with your doctor when the lump grows bigger and painful. A true lipoma is not cancerous. The case of lipoma being cancerous may be caused by errors in diagnosis and/or tissue sampling.