The uterus may develop fibroid growths, which technically are benign tumors. These growths are closely linked to the levels of estrogen in women, but little is known about why they develop. Fewer than one percent of such fibroids ever turn cancerous, although sometimes a benign fibroid may grow large enough that it must be removed to relieve pressure on other organs or to let a distorted uterus to return to its normal condition. There are several different types of uterine fibroids:
Subserosal fibroids occur just beneath the serosa, which is the thin, outer layer covering the uterus. These fibroids typically manifest as quite small bumps on the outside wall of the uterus but can grow considerably larger. Unless they are large and painful, subserosal fibroids usually do not require treatment.
Intramural fibroids originate inside the muscular walls of the uterus and may even reach the subserosal region. Overtime, the uterine cavity gets distorted and elongated due to the spread of intramural fibroids. These fibroids may be microscopic, or may grow bigger and bigger, even larger than berries. Symptoms are similar to those of subserosal or submucosal fibroid growths.
Submucosal fibroids are formed beneath the endometrium, the inner lining of the uterus cavity. These fibroids, also called intracavitary myomas, can disrupt the numerous blood vessels on the surface of the endometrium, causing pain, cramping and abnormal bleeding. Submucosal fibroids may hinder normal uterine contractions, grow large enough to block the fallopian tubes, or even become pedunculated and protrude into the vagina or cervix. These fibroids are linked with serious fertility problems. Intramural fibroids will occasionally extend into the cavity of the uterus, potentially resulting in the same problems as with submucosal fibroids. Problematic growths often can be removed with a hysteroscopic resection, which can be performed through the cervix without an incision.
Pedunculated fibroids extend from pedicles or stalks. These fibroids may erupt from either the serosal or the mucosal layer but typically are found on the outside of the uterus. Pedunculated fibroids may grow too large and cause pain by twisting. They usually do not require removal but when needed laparoscopy is used.
Transmural fibroids are the most invasive, extending from the submucosa to the serosa layer. These fibroids are present within the muscular walls but may even cover the whole thickness. A submucosal component and a subserosal component are involved. Abdominal myomectomy is the most widely used treatment.
After menopause, when estrogen production declines, the fibroids tend to shrink or disappear altogether. Hormones, environmental effects, and genetics are considered to be the underlying causes, but still it’s not clear.