Myoma of uterus, also called uterine fibroid tumors are nodules of smooth muscle cells and fibrous connective tissue that develop within the wall of the uterus or on the outer wall of the uterus, hence the name 'fibroid' tumor. Medically they are called uterine leiomyoma or myoma. Fibroids may grow as a single nodule or in clusters and may range in size from 1 mm to more than 20 cm (8 inches) in diameter. They may grow within the wall of the uterus or they may project into the interior cavity or toward the outer surface of the uterus. In rare cases, they may grow on stalks or peduncles projecting from the surface of the uterus.

Myoma of uterus (uterine fibroid tumors) can be classified into types as follows according to location:

Subserosal: These fibroids develop in the outer portion of the uterus and continue to grow outward. This type can cause the uterus to grow. 

Intramural: The most common type of fibroid. These develop within the uterine wall and expand making the uterus feel larger than normal (which may cause "bulk symptoms"). 

Pedunculated: Fibroids that grow on a small stalk that connects them to the inner or outer wall of the uterus.