What is adenomyosis?

Adenomyosis is defined as the presence of endometrial tissue, which normally lines the uterus, embedded within the myometrium, the muscular layer of the uterine wall. This condition often leads to dysmenorrhea (painful periods) and menorrhagia (heavy menstrual bleeding) due to the disrupted and abnormal uterine architecture and function, leading to increased uterine size and tenderness.

The description of adenomyosis as an "island of endometrial tissue within the myometrium" is accurate because it encapsulates the critical aspect of this condition: the invasion of the endometrial tissue into the smooth muscle of the uterus. This contrasts with other conditions that may also involve uterine tissue but fall under different categories, such as fibroids, which are solid tumors made up of smooth muscle and fibrous tissue, and ovarian tumors, which originate from the ovaries rather than the uterine lining. Malignant forms of endometriosis refer to a different, more severe manifestation where endometrial-like tissue causes significant pathology, often outside the uterus itself.