Uterine leiomyomas, also known as myomas or fibroids, is by far the most common benign uterine tumors. Other benign uterine growths, such as uterine vas¬cular tumors, are rare. Uterine leiomyomas are usually diagnosed on physical examination and can be furthered diagnosed with the use of gynecology microscopes. They may be subserosal, intramucosal, or submucosal in location within the uterus or located in the cervix, in the broad ligament or on pedicle. They are estimated to be pres¬ent in at least 20% of all women of reproductive age and may be discovered incidentally during routine annual examination. Leiomyomas are more common in African-American than in white women. Asymptomatic fibroids may be present, when samples are viewd under gynecologic microscopes, in 40-50% of women older than 40 years of age. They may occur singly but often are multiple. They may cause a range of symptoms, from abnormal bleeding to pelvic pressure, which may lead to the diagnosis. Less than one-half of uterine leiomyomas are estimated to produce symptoms.

The cause of uterine leiomyomas is unknown. Several microscopic studies have suggested that each leiomyoma arises from a single neoplastic cell within the smooth muscle of the my¬ometrium. There appears to be an increased familial incidence. Hormonal respon¬siveness and binding has been demonstrated in vitro. Fibroids have the potential to enlarge during pregnancy as well as to regress after menopause.

Fibroids, when viewed under gynecology microscopes, are discrete nodular tumors that vary in size and number. They may be microscopic or huge (a uterine weight of 74lb has been reported). They may cause symmetric uterine enlargement or they may distort the uterine contour significantly. The con¬sistency of an individual leiomyoma varies from hard and stony (as with a calcified leiomy¬oma) to soft (as with cystic degeneration), although the usual consistency is described as firm or rubbery. Although they do not have a true capsule, the margins of the tumor are blunt, non¬infiltrating, and pushing and are usually separated from the myometrium by a pseudocapsule of connective tissue, which allows easy enucleation at the time of surgery. There is usually one major blood vessel supplying each tumor. The cut surface is characteristically whorled.

Degenerative changes are reported in approximately two-thirds of all specimens. Leiomyomas, with an increased number of mitotic figures, may occur in various forms: 1) during pregnancy or in women taking progestational agents; 2) with necrosis; and 3) as a “smooth muscle tumor of uncertain malignant potential” (defined as having 5-9 mi• toses/l0 high-power fields (hpf) that do not demonstrate nuclear atypia or giant cells, or with a lower mitotic count (2-4 mitoses/l0 hpf) that does demonstrate atypical nuclear features or giant cells). Studies suggest that malignant degeneration of a preexist¬ing leiomyoma is extremely uncommon, occurring in less than 0.5%.

Leiomyosarcoma is a rare malignant neoplasm composed of cells that have smooth mus¬cle differentiation. The typical patient with leiomyosarcoma is in her mid-fifties and presents with abnormal bleeding. In most cases, diagnoses are made (postoper¬atively) after microscopic examination of a uterus removed because of suspected leiomy¬omas. Sarcomas that have a malignant behavior have more than 10 mitoses/hpf.

Uterine fibroids are frequently diagnosed on the basis of clinical findings of an enlarged, irregular uterus on pelvic examination. However, any pelvic tumor potentially can be con¬fused with an enlarged uterus.

The most common presenting symptom associated with fibroids, and the one that most fre¬quently leads to surgical intervention, is menorrhagia, which is reportedly present in one-¬third of women undergoing myomectomy. Chronic pelvic pain may also be present. Pain may be characterized as dysmenorrhea, dyspareunia, or pelvic pressure. Acute pain may result from torsion of a pedunculated leiomyoma or infarction and degen¬eration. The following urinary symptoms may be present:

1.    Frequency, which may result from extrinsic pressure on the bladder.
2.    Partial ureteral obstruction may be caused by pressure from large tumors at the pelvic brim. Reports suggest some degree of ureteral obstruction in 30-70% of tumors above the pelvic brim. Ureteral compression is 3-4 times more common on the right, because the left ureter is protected by the sigmoid colon.
3.    Rarely, complete urethral obstruction, resulting froni elevation of the base of the bladder by the cervical or lower uterine leiomyoma with impingement on the re¬gion of the internal sphincter, may occur.

Leiomyomas are an infrequent primary cause of infertility and have been reported as a sole cause in less than 3% of infertile patients. One review of myomectomies per¬formed for all indications noted a prior history of infertility in 27% of women. Preg¬nancy loss or complications can occur in women with leiomyomas, although most patients have uncomplicated pregnancies and deliveries. One study calculated a 10% rate ofpreg¬nancy complications in women with fibroids. Although growth of leiomyomas may occur with pregnancy, one study, with the use of gynecology microscopes, noted no demonstrable change in size (based on serial ultrasound examination) in 90% of the patients.

The following symptoms may infrequently be associated with leiomyomas:

1.    Rectosigmoid compression, with constipation or intestinal obstruction
2.    Prolapse of a pedunculated submucous tumor through the cervix, with associ¬ated symptoms of severe cramping and subsequent ulceration and infection (uterine inversion has also been reported)
3.    Venous stasis of the lower extremities and possible thrombophlebitis secondary to pelvic compression
4.    Polycythemia
5.    Ascites

Early detection and treatment of leiomyomas, with the use of gynecology microscopes, can help the patient in managing the symptoms and prevents other gynecologic complications from arising.