Hello, Since you have an ultrasound done by your gynaecologist, I assume you had other work up such as vaginitis swab testing is done to rule out vaginitis as well. Such discharge is a common finding of vaginal, cervical or pelvic infection. If the infectious cause has been ruled out, the current symptoms may be related to uterine or ovarian structural causes, especially your Ultrasound confirmed a mass in the uterus. Dark brown discharge seems to be old blood and any fibroids in the uterus can cause those dark brown discharge. Fibroids are not relatively uncommon findings and they are also called uterine myomas, leiomyomas, or fibromas. They are made of smooth muscle cells and fibrous connective tissue that develop in the uterus. Most of them are benign, so you do not need to have any advanced surgeries unless they are getting larger in size or causes unbearable symptoms. It sounds like you had an endometrial biopsy done. Since you had a biopsy done, you can continue to wait for results and follow up as scheduled. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Katie Lee, General & Family Physician