Ovarian remnant syndrome (ORS) is characterized by the presence of residual ovarian tissue after a woman has had surgery to remove one ovary or both ovaries (oophorectomy). Signs and symptoms may include pelvic pain, a pelvic mass, or the absence of menopause after oophorectomy. The condition may be caused by surgical factors leading to incomplete removal of ovarian tissue, including factors that limit surgical exposure of the ovary or compromise surgical technique. Factors may include pelvic adhesions (limiting ability to see the ovary or causing it to adhere to other tissues); anatomic variations; bleeding during surgery; or poor surgical technique. Treatment is indicated for people with symptoms and typically involves surgery to remove the residual tissue. Therapy for those who refuse surgery, cannot have surgery, or do not have a pelvic mass may include hormonal therapy to suppress ovarian function.

In most cases, symptoms occur within the first five years of the oophorectomy, although there are reports of ORS presenting 20 years after the initial surgery.

Surgical exploration and biopsy of possible ovarian tissue is required for the definitive diagnosis of ORS, and treatment by excision of the remnant ovarian tissue may be performed during the same procedure. For women who are not candidates for surgery, a clinical diagnosis can be made based on the symptoms and hormone levels (follicle-stimulating hormone and estradiol, after bilateral oophorectomy) and/or imaging findings consistent with the presence of residual ovarian tissue.

Treatment for ovarian remnant syndrome (ORS) is generally indicated for women with suspected ORS who have symptoms (such as pelvic pain); have a pelvic mass; or need or desire complete removal of tissue to decrease the risk of ovarian cancer (for example, BRCA mutationcarriers). The mainstay of treatment is surgery to remove the residual ovarian tissue. Women with ORS with a pelvic mass should have appropriate evaluation for malignancy (cancer). Hormonal therapy to suppress ovarian function is an alternative treatment for those who refuse surgery, or those who are not candidates for surgery.