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Well-Differentiated Liposarcoma

Last updated Jan. 9, 2019

Approved by: Maulik P. Purohit MD, MPH


Microscopic pathology image showing Well-Differentiated Liposarcoma. H&E stain.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Atypical Lipomatous Tumor
  • WDLPS (Well-Differentiated Liposarcoma)
  • WDLS (Well-Differentiated Liposarcoma)

What is Well-Differentiated Liposarcoma? (Definition/Background Information)

  • Well-Differentiated Liposarcomas (WDLSs) are usually slow-growing, malignant soft tissue tumors. They are well-circumscribed and typically present on the retroperitoneum, limbs, and mediastinum (chest region)
  • The cause of development of these tumors is unknown, but some genetic mutations have been observed
  • The treatment course includes complete surgical excision, which is usually curative. Since, Well-Differentiated Liposarcomas do not metastasize, the prognosis is typically excellent with early detection and removal of the tumor
  • The World Health Organization (WHO) classifies Well-Differentiated Liposarcomas into 4 types:
    • Lipoma-like Well-Differentiated Liposarcoma: These tumors have very good prognosis upon complete removal. However, since the tumors resemble benign lipomas, their diagnosis may be difficult
    • Sclerosing Well-Differentiated Liposarcoma: It is frequently found in the retroperitoneum followed by paratesticular region. In this tumor, there is the presence of fibrosis, when the tumor is examined by a pathologist under the microscope
    • Inflammatory Well-Differentiated Liposarcoma: Prominent inflammatory cells are found in the tumor, when it is examined by a pathologist under the microscope
    • Spindle Cell Well-Differentiated Liposarcoma: In addition to the retroperitoneum and spermatic cord, these tumors are also found to occur in the subcutaneous tissue. On a pathological examination of this soft tissue tumor under a microscope, there may be spindle cell areas, which give the tumor its name
  • A liposarcoma (LPS or LS) is a rare and malignant tumor of the fat cells. They are generally asymptomatic and can occur anywhere in the body
  • There are 4 main types of liposarcomas and these include:
    • Well-Differentiated Liposarcoma (WDLS): Approximately 45% of all types of liposarcomas are well-differentiated
    • Dedifferentiated Liposarcoma: It is a high-grade morphology tumor
    • Myxoid Liposarcoma: This type constitute 30% of all liposarcomas        
    • Pleomorphic Liposarcoma (PLS): It is the rarest type and constitute about 5% of all liposarcomas

Who gets Well-Differentiated Liposarcoma? (Age and Sex Distribution)

  • Well-Differentiated Liposarcoma is observed with a higher incidence in men, who are around 60 years old; though women may also be affected
  • There is no known ethnic or racial preference; WDLS is observed worldwide

What are the Risk Factors for Well-Differentiated Liposarcoma? (Predisposing Factors)

  • No clear risk factors have been identified for Well-Differentiated Liposarcoma occurrence

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Well-Differentiated Liposarcoma? (Etiology)

  • The exact cause and mechanism of formation of Well-Differentiated Liposarcoma is unknown
  • It is thought to occur spontaneously due to certain genetic mutations (chromosomal abnormalities)
  • Contrary to some beliefs, trauma does not contribute to the formation of liposarcomas. Current studies also do not support that liposarcomas arise from lipomas (very common, benign fatty tumors)

What are the Signs and Symptoms of Well-Differentiated Liposarcoma?

The signs and symptoms of Well-Differentiated Liposarcomas are mostly dependent upon the location of the tumors. The indications may include:

  • All tumors are slow-growing and painless
  • WDLS is frequently found on the abdominal region (retroperitoneum), extremities (arms and legs; most common location being the thigh), spermatic cord of the testes, and between the lungs in the chest (mediastinum)
  • If the tumor occurs on the thigh or spermatic cord, a painless lump may be observed. Thigh tumors may also cause leg pain and restricted movement (walking difficulties)
  • Tumors in the chest cavity may cause breathing difficulties
  • If it forms in the retroperitoneal space, the tumor may not cause any symptoms for a long period of time, until it grows to a large size and compresses the adjacent organs in the abdomen. This is one of the reasons why retroperitoneal tumors remain undetected during their early development stage

How is Well-Differentiated Liposarcoma Diagnosed?

Well-Differentiated Liposarcoma may be diagnosed by using the following tools and procedures:

  • A complete physical examination and thorough evaluation of the individual’s medical history
  • Radiological studies, such as x-ray, CT, MRI, or ultrasound scan of the affected region
  • Needle biopsy of tumor
  • Open biopsy of tumor: A tissue biopsy is performed and sent to a laboratory for a pathological examination, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Note: A needle biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a needle biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Well-Differentiated Liposarcoma?

Complications from Well-Differentiated Liposarcomas may include the following:

  • Large tumors in the retroperitoneal cavity can lead to weight loss, abdominal pain, frequent urination, and kidney failure due to compression of the kidney
  • Tumors in the leg may result in the formation of varicose veins
  • Damage to the muscles, vital nerves, and blood vessels, during surgery to remove WDLS
  • There is a probability of return of the tumor after surgery, in case it is incompletely removed. The incidence of recurrence is approximately 30%

How is Well-Differentiated Liposarcoma Treated?

Treatment measures for Well-Differentiated Liposarcoma include the following:

  • Complete surgical excision with clear margins usually results in a cure
  • Radiation therapy and chemotherapy are employed depending upon the specific case
  • Also, in some rare cases, limb amputation may have to be undertaken, in case of limb tumors
  • Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
  • Follow-up care with regular screening and check-ups are important, since the tumor may recur in some cases

How can Well-Differentiated Liposarcoma be Prevented?

Current medical research has not established a method  of preventing Well-Differentiated Liposarcomas.

What is the Prognosis of Well-Differentiated Liposarcoma? (Outcomes/Resolutions)

  • The prognosis is excellent with early surgical intervention. The mortality rate is 0%, if Well-Differentiated Liposarcomas are completely excised and removed with clear margins
  • Nevertheless, the outcome is dependent upon the site of the tumor. Tumors that can be completely excised have better prognosis than those that cannot be removed completely
  • The mortality is much higher (at 80%) if the tumor is present in the retroperitoneal region, because a complete excision of the tumor is difficult in many cases
  • Generally, the recurrence rate is about 30% when the tumor is incompletely removed

Additional and Relevant Useful Information for Well-Differentiated Liposarcoma:

In general, liposarcomas form approximately 5% of all sarcomas.

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 11, 2015
Last updated: Jan. 9, 2019