Fibroids, also known as uterine leiomyomas, are benign (noncancerous) growths that develop in the myometrium (the muscular wall of the uterus).  Fibroids are the most common pelvic tumor.  It has been estimated that one out of every 4 to 5 women older that 35 years has a uterine leiomyoma.  Although most fibroids are asymptomatic, sixty percent of all pelvic surgeries in women are performed for fibroids.  In fact fibroids are the most common cause of hysterectomies.  The tumors are most frequently found in the fourth and fifth decades of life.  The exact cause of their development is not clear, however it has been linked to a genetic predisposition and are more common in patients of African descent.  Fibroid sizes ranges from very small (pea size) to very large (size of a softball or larger).  They are categorized according to their location:

1.  Intramural fibroids are the most common and are situated in the muscle wall without proximity to the inside (endometrium) or outside (serosa) lining of the uterus.  They can cause heavier menstrual bleeding.

2.  Subserosal fibroids develop just under the outside lining of the uterus; these typically cause pelvic and back pain which may be from pressure of the tumor on adjacent structures.

3.  Submucosal fibroids are located just under the inside lining of the uterus (endometrium).  These can cause heavy bleeding.

Diagnosis

The diagnosis of uterine fibroids is usually made by a gynecologic internal pelvic exam.  Ultrasound examination or magnet resonance imaging (MRI) can be used to give more detailed information on the presence and location of the fibroids.  Diagnostic hysteroscopy, using a small scope placed through the vagina into the uterus, is useful to evaluate the presence of submucosal fibroids.

Symptoms

Most fibroids, even large ones, produce no symptoms.  In fact, many are discovered as incidental findings.  The mere presence of a fibroid does not necessitate its removal or active treatment unless there are clinically significant associated symptoms such as:

1.  Bleeding:  Any pattern of abnormal uterine bleeding from heavy and prolonged menstrual periods to unusual monthly bleeding between periods may occur.  The most common however, is excessive menstruation which may lead to severe anemia (low blood count).

2.  Pressure:  Large tumors may cause pressure on the bladder causing frequency and urgency of urination.  Pressure on the rectum may result in constipation and bloating.  With extremely large tumors, pressure on the pelvic veins may cause leg swelling or varicose veins.

3.  Pain:  Changes (degeneration) in the fibroid may result in pain or tenderness.  The onset is gradual and a dull, aching soreness is usual.  However the character and frequency of the pain is variable.  The pressure of large tumors pressing on the nearby organs may cause pain.  The most common type of discomfort is a sensation of pelvic heaviness.  Pain might also be experienced during sexual intercourse.