Adenomyosis (ad-uh-no-my-O-sis) occurs when endometrial tissue, which normally lines the uterus, exists within and grows into the muscular wall of the uterus. This happens most often late in your childbearing years after having children.
Adenomyosis differs from endometriosis — a condition in which the uterine lining becomes implanted outside the uterus — although women with adenomyosis often also have endometriosis. The cause of adenomyosis remains unknown, but the disease typically disappears after menopause. For women who experience severe discomfort from adenomyosis, certain treatments can help, but hysterectomy is the only cure.