A leiomyoma is a benign tumor that originates in smooth muscle tissue, such as that found in the intestinal walls and the heart. When present in the uterus, leiomyomas are commonly referred to as fibroids, a term that reflects the fact that in addition to smooth muscle, the growths characteristically contain fibrous connective tissue.

When associated with the uterus, which is the organ most commonly affected by the growths, leiomyomas are usually classified as one of several different types based upon their location. Growths positioned just under the uterine serosa are referred to as subserosal leiomyomas, whereas those found just beneath the endometrium are called submucous leiomyomas. Both of these types of tumors may be sessile or extended from a stalk (peduncular). Intramural leiomyomas, however, which are those that predominantly occur in the myometrium, are always attached directly to one or more tissues.

Uterine leiomyomas are very common, causing symptoms in nearly a quarter of all women of reproductive age. It is widely believed that a much larger proportion of the female population has uterine leiomyomas, but many of them are unaware of the benign tumors because they are asymptomatic. Studies show that black women are especially prone to developing leiomyomas, the prevalence among them being about 2 to 5 times that of white women. Researchers are not yet able to explain such statistics, for they do not know the cause of leiomyoma formation. Significant evidence does, however, link the growth of the tumors to hormone levels, especially estrogen.

Symptoms of uterine leiomyomas, when they do occur, may include heavy bleeding, pain or pressure in the pelvic region, frequent urination, abdomen distension, painful bowel movements, and anemia. Women with leiomyomas also frequently have difficulty becoming pregnant or carrying a pregnancy to term. For these reasons, many patients elect to receive treatment for the growths although they are benign.

The least invasive treatment for leiomyoma is hormone therapy to shrink the tumors, which is sometimes used as a first means of attack. Myomectomy, which involves the surgical removal of leiomyomas through an abdominal incision, and hysterectomy (the removal of the uterus) are much more invasive, but are generally more successful means of treatment for a larger proportion of women. The former procedure, however, sometimes results in uterine scarring that can compound fertility problems and the latter necessarily puts an end to fertility. Thus, for individuals who desire to conceive a child, fibroid embolization, which entails blocking blood vessels that nourish the tumor in order to “starve” the growth and causes no trauma to the uterus, is often the preferred type of treatment.

Uterine Leiomyoma at 10x Magnification - Recent research indicates that growth factors and genetics may be involved in the onset of some cases of uterine leiomyoma.

Uterine Leiomyoma at 20x Magnification - Leiomyomas tend to be firm to the touch and well circumscribed. The fibrous material they contain is thought arise as a result of the degeneration of muscle tissue.

Uterine Leiomyoma at 40x Magnification - Several different methods of treating leiomyomas are currently available so that the needs of a wide variety of patients can be met.