Definition of Adenomyosis:

Adenomyosis is uterine thickening that occurs when endometrial tissue, which normally lines the uterus, moves into the outer muscular walls of the uterus.

Causes, incidence, and risk factors:

The cause is unknown. Sometimes adenomyosis may cause a mass or growth within the uterus, which is called an adenomyoma.

The disease usually occurs in women older than 30 who have had children. It rarely occurs in women who have not carried a pregnancy to term.

Some form of adenomyosis affects 60% of women, but in most cases is does not cause symptoms.