Leiomyoma

Leiomyoma, commonly referred to as a fibroid when it occurs in the uterus, is a benign neoplasm arising from smooth muscle cells. It most often develops in the uterus but can also arise in other tissues containing smooth muscle, such as the gastrointestinal tract, urinary tract, skin, or soft tissues.

Histologically, leiomyomas are well circumscribed nodules composed of intersecting bundles of spindle-shaped smooth muscle cells with elongated, “cigar-shaped” nuclei. They typically lack significant cellular atypia and have low mitotic activity. They may vary in size and number and are usually described by their location within the uterus: submucosal, intramural, or subserosal.

Epidemiology and risk factors: leiomyomas are among the most common benign tumors in women of reproductive age. They often are asymptomatic and discovered incidentally. Risk factors reported include African descent, nulliparity, early menarche, and obesity. Growth of fibroids is influenced by hormones, particularly estrogen and progesterone.

Clinical features: uterine fibroids can cause heavy or prolonged menstrual bleeding, pelvic pressure or pain, frequent urination, constipation, and reproductive problems such as infertility or pregnancy loss. Many fibroids do not produce symptoms and may be found during routine exams or imaging for other reasons.

Diagnosis and management: initial evaluation includes pelvic examination and ultrasound; MRI may be used for detailed assessment or surgical planning. Treatment ranges from observation for asymptomatic cases to medical therapy (e.g., agents that reduce bleeding or shrink fibroids) and various procedures: myomectomy to preserve fertility, hysterectomy for definitive treatment, uterine artery embolization, or MR-guided focused ultrasound.

Prognosis: leiomyomas are benign with an excellent overall prognosis, though recurrence after treatment is possible; malignant transformation to leiomyosarcoma is rare.