Health Encyclopedia




National Organization for Rare Disorders, Inc.


It is possible that the main title of the report Leiomyosarcoma is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Leiomyosarcoma is a malignant (cancerous) tumor that arises from smooth muscle Cells 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, smooth muscle that lines the walls of the digestive tract causes wave-like contractions (peristalsis) that aid in the digestion and transport of food. Smooth muscles in the salivary glands cause the glands to squirt saliva into the mouth in response to taking a bite of food. Smooth muscle in the skin causes goose bumps to form in response to cold.

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 body sites 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. Leiomyosa usually spreads via the bloodstream. It is very rare to see it in lymphatics.

Since smooth muscle is found all over the body, a leiomyosarcoma can form almost anywhere where there are blood vessels, heart, liver, pancreas, genitourinary and gastrointestinal tract, the space behind the abdominal cavity (retroperitoneum), uterus, skin. The uterus is the most common location for a leiomyosarcoma. Most leiomyosarcomas of the gastrointestinal tract are now reclassified as gastrointestinal stromal tumors (GIST - see below)

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, nerves, tendons, and blood and lymph vessels. The exact cause of leiomyosarcoma, including uterine leiomyosarcoma, is unknown.


American Cancer Society, Inc.

250 Williams NW St

Ste 6000

Atlanta, GA 30303


Tel: (404)320-3333

Tel: (800)227-2345

TDD: (866)228-4327


National Cancer Institute

6116 Executive Blvd Suite 300

Bethesda, MD 20892-8322


Tel: (301)435-3848

Tel: (800)422-6237

TDD: (800)332-8615



OncoLink: The University of Pennsylvania Cancer Center Resource

3400 Spruce Street

2 Donner

Philadelphia, PA 19104-4283


Tel: (215)349-8895

Fax: (215)349-5445



Sarcoma Foundation of America

9899 Main Street Ste 204

Damascus, MD 20872


Tel: (301)253-8687

Fax: (301)253-8690



Sarcoma Alliance

775 E. Blithedale #334

Mill Valley, CA 94941


Tel: (415)381-7236

Fax: (415)381-7235



Rare Cancer Alliance

1649 North Pacana Way

Green Valley, AZ 85614



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223



76 Ellsworth Street

San Francisco, CA 94110

Tel: (415)826-0474



Northwest Sarcoma Foundation

P.O. Box 91460

Portland, OR 97291

Tel: (503)954-5740



For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated:  9/4/2012

Copyright  2008, 2012 National Organization for Rare Disorders, Inc.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.