Elizabeth A Stewart, MD
UpToDate performs a continuous review of over 350 journals and other resources. Updates are added as important new information is published. The literature review for version 14.3 is current through August 2006; this topic was last changed on August 9, 2006. The next version of UpToDate (15.1) will be released in February 2007.
INTRODUCTION — Adenomyosis refers to the presence of endometrial glands and stroma within the uterine musculature. Adenomyosis can be present as diffuse disease only apparent by microscopy or it can form nodules clinically resembling leiomyomas (termed adenomyomas). The ectopic endometrial tissue appears to induce hypertrophy and hyperplasia of the surrounding myometrium, producing a diffusely enlarged uterus. This more closely resembles the concentric enlargement of a pregnant uterus than the irregular enlargement of a leiomyomatous uterus and is often termed "globular" enlargement.
The three major types of benign tumors of the uterus are adenomyosis, leiomyomas (fibroids), and endometrial polyps. Adenomyosis will be reviewed here while leiomyomas and endometrial polyps are discussed separately. (See "Epidemiology, pathogenesis, diagnosis, and natural history of uterine leiomyomas", see "Treatment of uterine leiomyomas", and see "Endometrial polyps").
EPIDEMIOLOGY AND RISK FACTORS — The incidence of adenomyosis has not been accurately determined since the diagnosis can only be made by microscopic examination of the uterus. Although generally estimated to affect 20 percent of women, the incidence was approximately 65 percent in one study in which meticulous histopathological analysis of multiple myometrial sections was performed .
Adenomyosis appears to be more common among women with a history of childbearing than in nulliparous women . However, since diagnosis has typically been made only at the time of hysterectomy, this may be a confounder. A greater number of pregnancies is not associated with a higher risk of the disease . Prior uterine surgery may also be a risk factor . Symptoms typically occur in women between 40 and 50 years of age ().
Most women with this disorder have another pathologic