For a much more detailed guide, please have a look at our undifferentiated pleomorphic sarcoma information pack.

Undifferentiated pleomorphic sarcoma

Also known as:

  • UPS
  • Undifferentiated pleomorphic sarcoma not otherwise specified.
  • UPS- NOS

Older names no longer used:

  • malignant fibrous histiocytoma
  • MFH
  • malignant fibrohistiocytic tumours
  • malignant fibrous cytoma

What is UPS?

Undifferentiated pleomorphic sarcoma is often found as a painful, fast growing lump anywhere in the body, although they are more common in the legs. Under the microscope the cells appear undifferentiated, which means they don’t look like any normal mature cell. Pleomorphic means there will be a mixture of different forms of cell. These tumours are also genetically variable, so it is very hard to say what type of cell the cancer started in other than it came from the soft tissue.

A diagnosis of UPS is sometimes called a “diagnosis of exclusion” where it is used to label any soft tissue tumour that doesn’t fit any other description.

How rare is UPS?

Undifferentiated pleomorphic sarcoma is one of the more common sarcomas, although with only 1.2 cases per 100,000 each year in the UK, it is still very rare.

Who does UPS affect?

Although it can appear at any age, undifferentiated pleomorphic sarcoma tends to affect people between 50 and 70.

Why is RareCan interested in UPS?

RareCan is working to accelerate research into UPS by making it easier for researchers to connect with people who have it. You can help us do this by becoming a RareCan member and sharing information with us about your UPS cancer diagnosis. We will then get in touch with you about any research opportunities that might be suitable for you.

Looking for a different cancer type?

Please visit our ‘rare cancer list’ to search for your cancer type 

Useful links

If you are looking for further support with undifferentiated pleomorphic sarcoma we recommend the following websites:

Sarcoma UK

Sarcoma UK

Sarcoma UK is a charity for those with bone and soft tissue sarcoma diagnoses. They provide information on all types of sarcomas and have a patient support line to help assist with any queries and worries.