Adenomyosis

Adenomyosis

Adenomyosis is the presence of endometrial glands and supporting tissues in the muscle of the uterus where it would not occur normally. When the gland tissue grows during the menstrual cycle and then at menses tries to slough, the old tissue and blood cannot escape the uterine muscle and flow out of the cervix as part of normal menses. This trapping of the blood and tissue causes uterine pain in the form of monthly menstrual cramps. It also produces abnormal uterine bleeding when some of the blood finally escapes the muscle resulting in prolonged spotting. It more often occurs in the posterior wall of the uterus.

The background incidence of adenomyosis in all women either with or without symptoms is not known precisely because only in recent years has MRI imaging been able to diagnose adenomyosis without doing a hysterectomy. In studies of chronic pelvic pain in which women had hysterectomies, the incidence of adenomyosis is about 15% to 25% (1, 2). It seems to be about the same incidence in hysterectomy specimens from women without pain as from women with pain so it is possible that this represents the background incidence.

Cyclic, cramping uterine pain beginning later in reproductive life (generally after age 35) and often associated with prolonged and heavy menses is the classic presentation. It is difficult to differentiate from endometriosis if there is no abnormal bleeding and if it occurs earlier than age 40. Endometriosis tends to present earlier (20-40) and if there is abnormal bleeding it tends to be premenstrual spotting rather than heavy and prolonged nenses. The abnormal bleeding pattern of adenomyosis is similar to that found in perimenopause due to dysfunctional ovulatory problems.