Adenomyosis is sometimes called "the other endo," but it is not the same disease. If you have endometriosis, chances are, during one of your many internet searches hoping to self diagnose, you probably stumbled upon the word adenomyosis. What is Adenomyosis? According to the Mayo Clinic's website, adenomyosis occurs when tissue similar to the uterine lining grows into the uterus's muscular wall. This tissue still reacts to hormonal fluctuations throughout the menstrual cycle,