Get in touch with RARE Concierge.

Contact RARE Concierge


A rare soft tissue sarcoma characterized by a malignant space-occupying lesion most commonly located in the retroperitoneum or the inferior vena cava but also other soft tissues and composed of cells showing distinct features of smooth muscle cells. The tumor presents with mass effect depending on the location. It is capable of both local recurrence and distant metastasis while lymph node metastasis is rare. Prognosis largely depends on tumor location and size.

Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview.

Reference: Access aggregated data from Orphanet at Orphadata.

Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http: //www.orphadata.org. Data version October 2023.

Newly diagnosed with

Our RARE Concierge Services Guides are available to assist you by providing information, resources and connections as you navigate your rare disease journey.

Get Concierge Help

Advocacy Organizations

My Faulty Gene

My Faulty Gene is a nonprofit organization which provides information and assistance to any individual whose family medical history suggests genetic testing might be helpful in identifying an increased risk of disease due to a genetic mutation. We believe that everyone in need of genetic testing should have access to it.

My Little Sunshine Foundation

My Little Sunshine is a non-profit foundation dedicated to educating people about the importance of fertility preservation and making fertility resources accessible to all.


Educate and provide resources to POC with Rare Cancers

Clinical Trials

For a list of clinical trials in this disease area, please click here.