Leiomyoma of Uterus

What is a Leiomyoma of uterus?

A leiomyoma of uterus, also called a uterine leiomyoma or fibroid, is a benign monoclonal tumor arising from smooth muscle cells in the myometrium. It is the most common pelvic tumor in females. Estrogen and progesterone signaling drive the growth of these nodules. This dependence makes them more prevalent during reproductive years and often causes them to shrink after menopause.

These tumors may occur as single or multiple masses. Leiomyomas are very common, occurring in approximately 50% to 70% of females by menopause. Black patients tend to develop leiomyomas at younger ages and with a higher cumulative incidence and greater symptom burden.

What causes Leiomyomas?

The development of a leiomyoma of uterus involves the monoclonal proliferation of smooth muscle cells. Genetic mutations, particularly in MED12, frequently initiate this process alongside extracellular matrix deposition. Hormonal influences from estrogen, progesterone, and various growth factors amplify cell expansion. Leiomyomas may be solitary or multiple, but when numerous lesions coexist, leiomyomatosis develops.

Risk factors for development include early menarche, obesity, nulliparity, and a positive family history. Conversely, multiparity is associated with decreased risk. Uterine leiomyomatosis describes a state where the myometrium is diffusely filled with tumors. Leiomyomas are classified by location as intramural, submucosal, or subserosal. An intramural leiomyoma of uterus originates within the myometrium or muscular wall. A submucous leiomyoma of uterus grows toward the uterine cavity, while a subserous leiomyoma of uterus extends toward the serosal surface.

What signs and symptoms are associated with uterine leiomyomas?

Leiomyomas commonly present with heavy menstrual bleeding and pelvic pressure. Urinary frequency and reproductive dysfunction also occur, depending on the tumor size and number. Submucosal leiomyomas are most strongly associated with heavy menstrual bleeding and may impair fertility when they distort the uterine cavity. A subserous leiomyoma of uterus typically presents with bulk symptoms rather than excessive bleeding.

Individuals with multiple masses often develop a leiomyomatous uterus, identified by palpable, irregular uterine enlargement. Heavy or prolonged uterine bleeding in cases of leiomyomatosis can lead to iron deficiency anemia due to persistent blood loss. Intramural leiomyomas may contribute to heavy or prolonged menstrual bleeding and can also cause dysmenorrhea or pelvic pressure. These symptoms often correlate directly with the anatomical location of the lesions.

How is a Leiomyoma diagnosed?

Diagnosis of a leiomyoma of uterus begins with a detailed history and physical examination. Pelvic exams frequently reveal an irregular uterine contour or generalized enlargement. Pelvic ultrasound, using transvaginal and often transabdominal views, is the initial imaging test of choice. This imaging characterizes the location and estimates the size of the nodules.

MRI is used selectively for procedural planning or when the anatomy is complex or the diagnosis is uncertain. Laboratory studies assess for anemia and rule out alternative causes of abnormal bleeding. Diagnostic hysteroscopy can help evaluate intracavitary or submucosal fibroids when further definition of the uterine cavity is needed. On ultrasound, leiomyomas usually appear as well-circumscribed hypoechoic round masses, often with acoustic shadowing.

How is a Leiomyoma treated?

Management depends on symptom severity and reproductive desires. Observation is appropriate for asymptomatic cases. GnRH agonists, and in some settings GnRH antagonists, can reduce heavy menstrual bleeding and shrink fibroid and uterine volume, but their use is limited by hypoestrogenic adverse effects. Progestin-releasing intrauterine systems effectively reduce menstrual bleeding.

Uterine artery embolization is a minimally invasive option to occlude the blood vessels that feed the tumors. For symptomatic leiomyomas, procedural options include myomectomy for patients who desire uterine preservation and hysterectomy as definitive treatment for those who do not. The procedural approach depends on fibroid size, number, location, symptom pattern, and the patient’s fertility goals.

What are the most important facts to know about Leiomyomas?

• A leiomyoma of uterus is the most common pelvic tumor in females and is highly dependent on hormonal signaling.
• Genetic factors, specifically MED12 mutations, and reproductive history drive the development and proliferation of these tumors.
• The location of the tumor determines the symptoms, such as the heavy menstrual bleeding caused by a submucous leiomyoma of uterus.
• Bulk symptoms and pressure effects are more commonly associated with a subserous leiomyoma of uterus.
• Pelvic ultrasound is the initial imaging test, while MRI is reserved for selected cases requiring more detailed procedural planning or clarification of complex anatomy, such as leiomyomatosis.
• Treatment ranges from observation and bleeding-directed medical therapy to procedures such as myomectomy, uterine artery embolization, or hysterectomy, depending on symptoms and fertility goals.