Condition in which tissue more or less perfectly resembling the uterine mucous membrane (the endometrium) and containing typical endometrial granular and stromal elements occurs aberrantly in various locations in the pelvic cavity.

Endometriosis is a disease in which cells like those in the endometrium, the layer of tissue that normally covers the inside of the uterus, grow outside the uterus. It occurs in humans and a limited number of menstruating mammals...