Fibroids or leiomyomata (myomas) are common non-cancerous growths that usually occur on or on the muscular wall of the uterus. One cell divides repeatedly and grows a smooth appearance. fibroids separated from the uterine wall Almost half of women over 50 have this kind of growth. It's more common in African American women than Caucasians. Nodules can grow into a single nodule or several nodules of different sizes.