Endometriosis can afflict odd places like knees and colon. I had a case where they resected an entire right colon cause it presented as an obstruction and looked like cancer. They look the same on imaging as any other cancer and tuberculosis. Most are managed as hormonal therapy but resection usually does it, there is still a chance for recurrence though.
What makes this case rare isnt the endometriotic cyst part which ia common but the atypical epithelium that transformed associated with it.