Most common during the reproductive age. The growth of leiomyoma is linked to estrogen stimulation. May exist without symptoms or may produce endometrial bleeding, pain, disorders of the urinary tract, and may lead to impaired fertility. Grossly appear as sharply circumscribed, round, firm, gray-white tumors. Are composed of spindle smooth muscle cells.
Mitosis is uncommon.
May undergo hemorrhage, necrosis, calcification and cystic degeneration. Malignant transformation is rare.