Adenomyosis is uterine thickening that occurs when endometrial tissue, which normally lines the uterus, moves into the outer muscular walls of the uterus. Its 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. The symptoms include long-term or heavy menstrual bleeding, painful menstruation, which gets increasing worse and pelvic pain during intercourse. The ‘benign invasion of endometrium into myometrium’ that occurs in adenomyosis can lead to enlargement of the uterus and reactive hyperplasia and hypertrophy of the neighbouring myometrium (Bird et al., 1972).