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

• Leiomyosarcoma of Retroperitoneum
• LMS of Retroperitoneum
• Retroperitoneal LMS 

What is Retroperitoneal Leiomyosarcoma? (Definition/Background Information)

• Leiomyosarcoma (LMS) is a rare type of connective tissue cancer, accounting for 5-10% of all soft tissue sarcomas (a type of cancer)
• Experimental analysis point to the cell line origin for leiomyosarcoma being smooth muscle cells. Smooth muscles are muscles that are not voluntarily controlled. Due to the bounty of smooth muscle throughout the body, any individual is susceptible to LMS, although the elderly are more prone to the condition
• Retroperitoneal Leiomyosarcoma is predominantly observed in elderly women. This aggressive form of cancer is found in the abdominal cavity and pelvic regions
• There are currently no established risk factors, causes, or preventive methods for Leiomyosarcoma of Retroperitoneum
• The signs and symptoms include abdominal pain, frequent urination, loss of appetite, and sensation of pressure in the pelvic area. The complications are dependent upon the stage of the cancer
• Treatment for the condition is through a combination of surgery, chemotherapy, and radiation therapy. But, the prognosis of Leiomyosarcoma of Retroperitoneum depends on the cancer stage and many other factors

Who gets Retroperitoneal Leiomyosarcoma? (Age and Sex Distribution)

• Typically, women between the ages of 50 and 70 years are susceptible to Leiomyosarcoma of Retroperitoneum. However, men may also be affected
• There are no known geographical, racial, or ethnic preferences; this cancer type is found to occur worldwide

What are the Risk Factors for Retroperitoneal Leiomyosarcoma? (Predisposing Factors)

There are no well-established risk factors for Retroperitoneal Leiomyosarcoma. Nevertheless, the following may be noted:

• Genetic mutations have been observed in the tumors, which can potentially increase the risk
• High-dose radiation exposure to the abdomen or pelvis, such as pelvic radiation therapy, is believed to increase the risks of leiomyosarcoma
• Immunocompromised patients infected by Epstein-Barr virus seem to be predisposed to LMS. The reason for this is not understood, yet there seems to be a definite correlation between the viral infection and the arising of multiple, synchronized leiomyosarcomas

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 Retroperitoneal Leiomyosarcoma? (Etiology)

• Currently, there are no known causes for Retroperitoneal Leiomyosarcoma
• As smooth muscles are found widely throughout the body, any individual is susceptible to leiomyosarcoma. However, due to the rarity of the cancer, it is difficult to determine what exactly leads to the formation of Retroperitoneal LMS
• Contrary to some beliefs, trauma does not contribute to the formation of leiomyosarcomas. Current studies also do not support that leiomyosarcomas arise from leiomyomas (benign tumors of smooth muscle)

What are the Signs and Symptoms of Retroperitoneal Leiomyosarcoma?

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.

The signs and symptoms of Retroperitoneal Leiomyosarcoma include:

• Unusual feeling of fullness in the pelvic or abdominal region (retroperitoneal cavity)
• Pain in the pelvic or abdominal region
• Frequent urination
• Weight loss
• Weakness, lethargy
• Fever

It is important to note that there are no specific clinical features that can be used to identify leiomyosarcoma from other soft tissue sarcomas of the pelvis. Biopsies are necessary to determine if leiomyosarcoma is present.

How is Retroperitoneal Leiomyosarcoma Diagnosed?

A diagnosis of Retroperitoneal Leiomyosarcoma may be made by using the following resources:

• Complete physical examination and evaluation of medical (and family) history
• Initial diagnostic tests may include:
• Abdominal or pelvic ultrasound can provide an image of the abdomen and the surrounding pelvic organs, along with determination of the presence of a tumor
• MRI scans can be used to observe if the tumor has the characteristics of cancer, along with visualizing the cancer spread (if it has spread to other areas)
• Plain radiographs of the chest can provide evidence if the tumor has spread to the lungs
• CT scans can be used to determine if metastasis has occurred
• Whole body PET scan to determine the stage of the tumor
• Needle biopsy of tumor: 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
• 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

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 possible Complications of Retroperitoneal Leiomyosarcoma?

The possible complications of Retroperitoneal Leiomyosarcoma include:

• The rarity of the condition may cause a delayed diagnosis, leading to metastasis
• Large tumors in the retroperitoneal cavity can lead to weight loss, abdominal pain, frequent urination, and kidney failure due to compression of the kidney
• The tumor may also adversely impact adjoining/surrounding structures, such as the nerves and joints, leading to discomfort or a loss of feeling
• Metastasis of the tumor to other body regions, frequently to the lungs and liver
• Damage to the muscles, vital nerves, and blood vessels, during surgery to remove the tumor

How is Retroperitoneal Leiomyosarcoma Treated?

Surgery is the most common treatment for Retroperitoneal Leiomyosarcomas.

• Complete excision and removal of the tumor with clear margins
• Radiation therapy and chemotherapy are employed depending upon each specific case
• Other than surgery, LMS provides a treatment challenge due to the observed resistance to chemotherapy and radiation therapy

Once treatment is complete, it is recommended that the patient schedule regular check-ups, based on the recommendation of the healthcare professional treating them.

How can Retroperitoneal Leiomyosarcoma be Prevented?

There are currently no known methods of preventing Retroperitoneal Leiomyosarcoma.

What is the Prognosis of Retroperitoneal Leiomyosarcoma? (Outcomes/Resolutions)

• The prognosis for Retroperitoneal Leiomyosarcoma depends on the stage of the leiomyosarcoma upon diagnosis. Tumors that can be completely excised have better prognosis than those that cannot be completely removed
• The mortality rate is high, since the tumor is present in the retroperitoneal region; a complete excision of the tumor is difficult in many cases

It is important to schedule and attend follow-up appointments with the healthcare provider. Many patients with metastatic or locally advanced tumors may be referred for clinical trials for experimental treatment options.

Additional and Relevant Useful Information for Retroperitoneal Leiomyosarcoma:

Although leiomyosarcomas are rare cancer forms, there are many online discussion groups, local groups, and sarcoma centers available to provide help and support.