Some other uterine conditions can cause signs and symptoms similar to those of adenomyosis, making adenomyosis difficult to diagnose. These conditions include fibroid tumors (leiomyomas), uterine cells growing outside the uterus (endometriosis) and growths in the uterine lining (endometrial polyps).
https://www.mayoclinic.org/diseases-conditions/adenomyosis/diagnosis-treatment/drc-20369143

