These tumours develop in the muscle or connective tissue of the uterus. They are different from the more common type of uterine cancer called endometrial cancer, which develops in the lining of the uterus. Uterine sarcomas account for only about 1% of all uterine cancers. 

 

There are three main types of uterine sarcomas: 

 

1.  Leiomyosarcoma: This is the most common type of uterine sarcoma. It develops in the smooth muscle of the uterus and typically affects women in their 40s and 50s. 

 

2.  Endometrial stromal sarcoma: This type of sarcoma develops in the connective tissue of the uterus. It is less common than leiomyosarcoma and usually affects women in their 30s and 40s. 

 

3.  Undifferentiated sarcoma: This is a rare and aggressive type of uterine sarcoma that is difficult to treat. It does not resemble any specific tissue type and can occur at any age.