NORD is very grateful to Dennis S. Chi, MD, Deputy Chief, Gynecology Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, for assistance in the preparation of this report.
A uterine leiomyosarcoma is a rare malignant (cancerous) tumor that arises from the smooth muscle lining the walls of the uterus (myometrium). There are essentially two types of muscles in the body: voluntary and involuntary. Smooth muscles are involuntary muscles; the brain has no conscious control over them. Smooth muscles react involuntarily in response to various stimuli. For example, the myometrium stretches during pregnancy to help accommodate the fetus and contracts during labor to help push out a baby during childbirth. Leiomyosarcoma is a form of cancer. The term "cancer" refers to a group of diseases characterized by abnormal, uncontrolled cellular growth that invades surrounding tissues and may spread (metastasize) to distant bodily tissues or organs via the bloodstream, the lymphatic system, or other means. Different forms of cancer, including leiomyosarcomas, may be classified based upon the cell type involved, the specific nature of the malignancy, and the disease's clinical course. Leiomyosarcoma is classified as a soft tissue sarcoma. Sarcomas are malignant tumors that arise from the connective tissue, which connects, supports and surrounds various structures and organs in the body. Soft tissue includes fat, muscle, never, tendons, tissue surrounding the joints (synovial tissue), and blood and lymph vessels. The exact cause of leiomyosarcoma, including uterine leiomyosarcoma, is unknown.
Symptoms of uterine leiomyosarcoma may vary from case to case depending upon the exact location, size and progression of the tumor. Many women will not have any apparent symptoms (asymptomatic). The most common symptom is abnormal bleeding from the vagina and the uterus. Postmenopausal bleeding is an important factor that may indicate a uterine leiomyosarcoma.
Additional symptoms may occur including pressure or pain affecting the pelvis or stomach, abnormal vaginal discharge, and a change in bladder or bowel habits. General symptoms often associated with cancer include fatigue, fever, weight loss, and a general feeling of ill health (malaise).
Uterine leiomyosarcomas are malignant and may spread (metastasize) locally and to other areas of the body, especially the lungs and liver often causing life-threatening complications. Leiomyosarcomas recur in more than half of the cases sometimes within eight to 16 months of the initial diagnosis and treatment.
The exact cause of uterine leiomyosarcoma is unknown. They often occur spontaneously, for no apparent reason. In extremely rare cases, some researchers believe they may signify a malignant change (transformation) of a benign (noncancerous) fibroid. However, other researchers argue that malignant transformation of fibroids is unproven. Fibroids are the most common tumors affecting women and often appear during childbearing years. Fibroids may also be known as leiomyomas or myomas. Most fibroids do not cause any symptoms or complications.
Researchers speculate that genetic and immunologic abnormalities, environmental factors (e.g., exposure to ultraviolet rays, certain chemicals, ionizing radiation), diet, stress, and/or other factors may play contributing roles in causing specific types of cancer. Investigators are conducting ongoing basic research to learn more about the many factors that may result in cancer.
In individuals with cancer, including leiomyosarcoma, malignancies may develop due to abnormal changes in the structure and orientation of certain cells known as oncogenes or tumor suppressor genes. Oncogenes control cell growth; tumor suppressor genes control cell division and ensure that cells die at the proper time. The specific cause of changes to these genes is unknown. However, current research suggests that abnormalities of DNA (deoxyribonucleic acid), which is the carrier of the body’s genetic code, are the underlying basis of cellular malignant transformation. These abnormal genetic changes may occur spontaneously for unknown reasons or, more rarely, may be inherited.
Leiomyosarcomas are associated with specific genetic and environmental risk factors. Certain inherited conditions that run in families may increase the risk of developing a leiomyosarcoma. These disorders include Gardner syndrome, Li-Fraumeni syndrome, Werner syndrome, neurofibromatosis and several immune deficiency syndromes. The exact association between leiomyosarcoma and these disorders is not understood. (For more information on these disorders, choose the specific disorder name as your search term in the Rare Disease Database.)
Researchers have speculated that exposure to high dose radiation and certain chemicals (e.g., herbicides) may be linked to an increased risk of developing leiomyosarcoma but no definitive link has been established.
Uterine leiomyosarcoma is an extremely rare form of cancer, estimated to occur in 6 out of every 1,000,000 women in the United States each year. The average age at diagnosis is 51. Uterine leiomyosarcomas account for 1-2 percent of all malignant tumors of the uterus.
Leiomyosarcoma is a form of soft tissue sarcoma. According to the American Cancer Society, 9,530 new cases of soft tissue sarcoma will occur in the United States in 2006. Soft tissue sarcomas affect men slightly more often than women and occur more often in adults than children and adolescents.
The diagnosis of a uterine leiomyosarcoma is most commonly made incidentally when affected individuals are operated on for benign smooth muscle tumors of the uterus (leiomyomas or fibroids). The pathologic review of the fibroid surgery specimens may reveal certain characteristics under the microscope that are more characteristic of a leiomyosarcoma than a benign myoma. Thus, pathologic review is key diagnostic aspect is distinguishing malignant leiomyosarcoma from its benign counterpart, the leiomyoma.
Specialized imaging techniques may be used to help evaluate the size, placement, and extension of the tumor and to serve as an aid for future surgical procedures, among individuals with uterine leiomyosarcomas. Such imaging techniques may include computerized tomography (CT) scanning, magnetic resonance imaging (MRI) and ultrasound. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues. During an ultrasound reflected sound waves create an image of the uterus. Laboratory tests and specialized imaging tests may also be conducted to determine possible infiltration of regional lymph nodes and the presence of distant metastases.
To confirm the diagnosis of metastatic leiomyosarcoma a fine-needle aspiration may be performed. Fine-need aspiration (FNA) is a diagnostic technique in which a thin, hollow needle is passed through the skin and inserted into the nodule or mass to withdraw small samples of tissue. The collected tissue is then studied under a microscope. In some cases, FNA may prove inconclusive and physicians may perform an incisional biopsy. During an incisional biopsy, a small sample tissue is surgically removed and sent to a pathology laboratory where it is processed and studied to determine its microscopic structure and makeup (histopathology).
The therapeutic management of individuals with a uterine leiomyosarcoma may require the coordinated efforts of a team of medical professionals, such as physicians who specialize in the diagnosis and treatment of gynecologic cancers (gynecologic oncologists), specialists in the use of radiation to treat cancer (radiation oncologists), specialists in the use of chemotherapy to treat cancer (medical oncologists), oncology nurses, and other specialists.
Specific therapeutic procedures and interventions may vary, depending upon numerous factors, such as primary tumor location, extent of the primary tumor (stage), and degree of malignancy (grade); whether the tumor has spread to lymph nodes or distant sites; an individual’s age and general health; and/or other elements. Decisions concerning the use of particular interventions should be made by physicians and other members of the health care team in careful consultation with the patient, based upon the specifics of his or her case; a thorough discussion of the potential benefits and risks; patient preference; and other appropriate factors.
The primary form of treatment for a uterine leiomyosarcoma is surgical removal of the entire tumor and any affected tissue. Total surgical removal of the uterus (hysterectomy) is usually performed. Usually, surgical removal of the fallopian tubes and ovaries (bilateral salpingo-oophorectomy) may also be recommended, especially for women who are menopausal or have metastases.
Anti-cancer drugs used alone or combination (chemotherapy) and radiation therapy have been used to treat individuals with leiomyosarcoma following surgery (adjuvant therapy) with limited benefit. Investigational therapies are underway to develop new chemotherapeutic combinations that may prove beneficial in treating leiomyosarcomas. In some cases, radiation therapy may be used before surgery to reduce the size of a tumor.
Because leiomyosarcomas have a high risk of recurrence, individuals should be examined routinely after surgery.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Some current clinical trials also are posted on the following page on the NORD website:
For information about clinical trials sponsored by private sources, contact:
For information about clinical trials conducted in Europe, contact:
Medical centers and hospitals that specialize in sarcomas (sarcoma centers) are conducting research into new treatments for individuals with soft tissue sarcomas including new chemotherapeutic drugs, new combinations of chemotherapeutic drugs, angiogenesis inhibitors that prevent the formation of new blood vessels needed to supply blood tumors, and various biologic therapies that involve the immune system in fighting cancer. (For information on sarcoma centers, contact the sarcoma specific nonprofit organizations listed in the Resources section of this report.)
Researchers are studying new diagnostic techniques for detecting uterine leiomyosarcomas including MRI-guided biopsies and a test that combines an MRI scan with a blood test for serum lactic dehydrogenase (LDH). Elevated LDH levels may indicate tissue damage caused by disease such as cancer. More research is necessary to determine the accuracy, safety and effectiveness of such techniques.
Clinical trials are underway to study the use of liposomal doxorubicin chemotherapy in individuals with advanced or recurrent uterine leiomyosarcomas. Another trial is exploring the combination of gemcitabine and docetaxel. Additional drugs being studied for individuals with uterine leiomyosarcomas, either alone or in various combinations, include cyclophosphamide, dacarbazine, topotecan, paclitaxel, etoposide, and hydroxyurea. More research is necessary to determine the long-term safety and effectiveness of these potential treatments for individuals with uterine leiomyosarcomas.
Clinical trials are underway to determine the effectiveness of temozolomide for the treatment of women with uterine leiomyosarcoma that has spread (metastasized) or cannot be treated surgically (unresectable). In initial clinical trials, temozolomide was well tolerated and demonstrated promising therapeutic benefit for affected individuals. More research is necessary to determine the long-term safety and effectiveness of this potential treatment for women with uterine leiomyosarcoma.
Contact for additional information about uterine leiomyosarcoma:
Dennis S. Chi, MD
Deputy Chief, Gynecology Service
Department of Surgery
Memorial Sloan Kettering Cancer Center
1275 York Avenue H 1304
New York, NY 10065
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Talbot SM, Keohan ML, Hesdorffer M, et al., A phase II trial of temozolomide in patients with unresectable or metastatic soft tissue sarcoma. Cancer. 2003;98:1942-6.
Goto A, Takeuchi S, Sugimura K, Maruo T. Usefulness of Gd-DTPA contrast-enhanced dynamic MRI and serum determination of LDH and its isozymes in the differential diagnosis of leiomyosarcoma from degenerated leiomyoma of the uterus. Int J Gynecol Cancer. 2002;12:354-61.
Chiang JW. Uterine Cancer. eMedicine. http://emedicine.medscape.com/article/258148-overview Updated: Jun 17, 2013. Accessed May 12, 2015.
Mayo Foundation for Medical Education and Research. Soft tissue sarcoma. http://www.mayoclinic.com/health/soft-tissue-sarcoma/DS00601 Updated Jan. 24, 2015. Accessed May 12, 2015.
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