Pleomorphic Liposarcoma
Pleomorphic liposarcoma is a rare and aggressive cancer that develops in fat tissue, most commonly in the arms and legs. It is the least common but most aggressive type of liposarcoma, characterized by abnormally shaped fat cells and a high risk of spreading to other parts of the body.
Table of contents
- What is Pleomorphic Liposarcoma?
- Medical Classification Codes
- Subtype
- Signs and Symptoms
- Where It Occurs
- Who Is Affected
- How It Is Diagnosed
- Treatment Options
- After Treatment
- Outlook
What is Pleomorphic Liposarcoma?
Pleomorphic liposarcoma is a rare and aggressive type of cancer that develops in fat tissue. It is characterized by the presence of pleomorphic lipoblasts, which are abnormally shaped immature fat cells, within a high-grade cancer. The term “pleomorphic” means that the cells vary in size, shape, and structure, growing in a very disorganized manner.[1]
Unlike other types of liposarcoma, pleomorphic liposarcoma does not show any features of well-differentiated liposarcoma or other tissue types. This makes it distinct from other fat tissue cancers.[1] It is considered the rarest but most aggressive subtype of liposarcoma, accounting for less than 5% to 10% of all liposarcoma cases.[1][3][4]
The disease can be very aggressive, growing very fast and quickly spreading from where it started to other areas of the body, most commonly to the lungs.[2][4]
Medical Classification Codes
C49.9
C0205825
10073138
PLS
Subtype
Pleomorphic liposarcoma has one recognized subtype called epithelioid liposarcoma.[1]
Signs and Symptoms
The symptoms of pleomorphic liposarcoma can vary depending on the size and location of the tumor. Most patients report a rapidly growing mass that is usually painless, typically appearing over a short period of 3 to 6 months before diagnosis.[1] However, some patients do experience pain, and others may have symptoms related to the tumor’s location.[1]
When pleomorphic liposarcoma develops in the arms or legs, it may cause the following symptoms:[3]
- A lump that grows persistently
- Swelling or numbness in the area around the lump
- Weakness of the affected arm or leg
When the tumor forms in the torso, such as in the abdomen or behind the abdominal cavity (the retroperitoneum, which is the space behind the abdominal cavity), it may cause:[3]
- Stomach pain or cramping
- Gradually increasing size of the abdomen
Most tumors grow very slowly and rarely cause pain initially. You may not notice any changes in your body unless you see a large bump on your arm or leg that doesn’t go away or gets larger. A tumor may cause pain if it presses on a nerve.[2]
Where It Occurs
- Lower limbs
- Upper limbs
- Trunk wall
- Retroperitoneum
- Spermatic cord
Pleomorphic liposarcoma occurs in the arms and legs (extremities) in about two-thirds of cases, more commonly in the lower limbs than the upper limbs. The trunk wall, the space behind the abdominal cavity, and the spermatic cord are less frequently affected.[1]
Rare sites where the tumor can develop include the space between the lungs (the mediastinum), the heart, the lining of the lungs and chest cavity (the pleura), the breast, scalp, colon, and the eye socket (the orbit).[1]
Most cases arise in deep soft tissue, but about 25% develop in the layer of fat beneath the skin (called subcutaneous fat). Cases that develop purely in the skin itself are very rare.[1]
Who Is Affected
Pleomorphic liposarcoma is a rare disease. The incidence is approximately 1 in 2,000,000 people per year.[4] In England, an average of 46 cases are diagnosed every year.[3]
Most cases occur in adults in later life. The peak incidence is in the seventh decade of life, with the typical age at diagnosis being between 50 and 70 years old.[1][4] The median age at diagnosis is 70 years old.[3]
The disease shows a slightly higher incidence in males than females.[1][3] Cases in children are extremely rare, and are described as exceptional.[1]
How It Is Diagnosed
Diagnosis of pleomorphic liposarcoma usually begins when a patient notices a lump on the arms, legs, or torso. It can also be found during an investigation of other symptoms or during a routine operation. The process may start with a visit to your general practitioner, who will examine you and then refer you to a specialist doctor.[3]
A specialist doctor will diagnose the disease through a series of tests, which may include:[3]
- Physical examination – The doctor will look at and feel any lump to assess its size, location, and hardness
- Imaging scans – Pictures of the inside of the body are taken using computed tomography (CT) or magnetic resonance imaging (MRI)[4]
- Biopsy – A tissue sample is taken and tested. For tumors in the arms or legs, multiple core biopsies are generally performed to make the diagnosis. For chest and abdominal tumors, a biopsy may not be needed before surgery unless the tumor cannot be completely removed or the surgery would cause serious complications.[4]
Under the microscope, pleomorphic liposarcoma contains a variable number of pleomorphic lipoblasts. Bleeding and tissue death (necrosis) are commonly observed in these tumors.[4]
The disease can often be mistaken for other types of cancers, such as myxofibrosarcoma or pleomorphic undifferentiated sarcoma.[4]
Treatment Options
Surgery is the main treatment for pleomorphic liposarcoma. The treatment approach involves surgical removal of the tumor along with surrounding normal tissue. This is known as taking a margin, which helps ensure that any cancer cells not visible to the naked eye are removed along with the tumor. This can reduce the risk of the cancer coming back.[3][4]
In rare cases, surgical amputation of the limb may be necessary.[3][4]
Some larger tumors, particularly those greater than 5 to 8 centimeters or those that are difficult to remove completely, may be treated with chemotherapy before surgery.[3][4]
Radiotherapy (radiation therapy) may also be given before or after surgery if the surgical margin is narrow or if cancer cells are found at the edge of the removed tissue.[3][4]
The disease can be staged using the American Joint Committee on Cancer (AJCC) and Union for International Cancer Control (UICC) TNM staging systems.[1]
After Treatment
After treatment, you will have regular follow-up appointments for several years. You should receive a follow-up schedule from your specialist nurse. The usual practice includes:[3]
- A chance to discuss symptoms
- An examination to look for any signs of the cancer returning, which may include an MRI or ultrasound if required after examination
- A chest X-ray to check for any secondary cancers occurring in the lungs
Lifelong follow-up is recommended to monitor for recurrence at the initial site as well as spread to distant parts of the body (distant metastasis).[4]
Outlook
Pleomorphic liposarcoma has the poorest outlook of all liposarcoma subtypes. It carries a high risk of the cancer coming back (recurrence) and spreading to other parts of the body (metastasis). The risk of metastasis is greater than 50%, with spread occurring most commonly to the lungs. This spread is often rapid and can lead to death.[3][4]
The five-year survival rate is 59%.[4] Early detection and treatment are essential for improving outcomes.
