Ovarian remnant syndrome (ORS) is an uncommon problem, but one that seems to be increasing in incidence and one that is important to diagnose and treat properly, as well as prevent. Retrospective cohort studies published in the past 15 years or so have improved our understanding of its presentation and the outcomes of surgical management – and recent literature has demonstrated that a minimally invasive surgical approach with either conventional laparoscopy or robot-assisted laparoscopy yields improved outcomes in a skilled surgeon’s hands.
Diagnosis is based on clinical history and should be further supported with imaging and laboratory evaluation. A definitive diagnosis of the disease comes through surgical intervention and pathological findings.
Surgery therefore is technically challenging, usually requiring complete ureterolysis, careful adhesiolysis (often enterolysis), and excision of much of the pelvic sidewall peritoneum with extirpation of the remnant and endometriosis. High ligation of the ovarian vasculature also often is required.
This complexity and the consequent risk of intraoperative injury to the bowel, bladder, and ureters requires careful preoperative preparation. When an ovarian remnant is suspected, it may be important to have other surgeons – such as gynecologic oncologists, urologists, colorectal surgeons, or general surgeons – either present or on standby during the surgical intervention. In expert hands, surgical intervention has been shown to resolve or improve pain in the majority of patients, with no recurrence of the syndrome.
Diagnosis of ORS
Courtesy Dr. Charles E. Miller and Dr. Kirsten J. Sasaki
Patients with ORS have had previous oophorectomies with incomplete removal of ovarian tissue. Pelvic pain, either cyclical or most commonly chronic, is a common symptom. Other symptoms can include dyspareunia, dysuria and other urinary symptoms, and bowel symptoms. Ovarian remnants may have an expanding cystic structure – oftentimes secondary to endometriosis – that causes mass-like effects leading to pain and inflammation and to symptoms such as low back pain, constipation, and even urinary retention.
It also is important to discuss the patient’s history of menopausal symptoms, because the absence of these symptoms after oophorectomy may be a sign that ovarian tissue has been left behind. Menopausal symptoms do not exclude the diagnosis, however. Endometriosis, extensive surgical history, and other diseases that lead to significant adhesion formation – and a higher risk of incomplete removal of ovarian tissue, theoretically – also should be explored during history-taking.
Laboratory assessment of serum follicle-stimulating hormone (FSH) and estradiol can be helpful. Values that are indicative of ovarian function – FSH less than 30 mIU/mL and estradiol greater than 35 pg/mL – point towards ORS, but the absence of such premenopausal values should not rule out the possibility of an ovarian remnant.
The literature shows that FSH and estradiol levels are variable in women with ORS. A retrospective review published in 2005 by, and colleagues at the Mayo Clinic, Scottsdale, Ariz., and Rochester, Minn., involved 186 patients treated surgically from 1985 to 2003 with a mean follow-up, via questionnaire, of 1.2 years. This is the largest series published thus far of patients with pathologically confirmed ORS. It reported premenopausal levels of FSH and estradiol in 69% and 63% of patients, respectively, who had preoperative hormonal evaluations.1
In another retrospective cohort study published in 2011 of 30 women – also with pathologically confirmed ovarian remnants – Deborah Arden, MD, and, of the University of Pittsburgh Medical Center reported premenopausal levels of FSH and estradiol in 59% and 71%, respectively, of women whose concentrations were measured.2
ORS often involves a pelvic mass, and preoperative imaging is important in this regard. In Dr. Magtibay’s series, a pelvic mass was identified in 93%, 92%, and 78% of those who were imaged presurgically with ultrasonography, computed tomography, and magnetic resonance imaging, respectively.1 As with laboratory testing, however, a negative result does not rule out the presence of an ovarian remnant.
Some authors have advocated the use of clomiphene citrate stimulation before preoperative imaging – or before repeat imaging – to identify remnant ovarian tissue. Typically, clomiphene citrate 100 mg is administered for 10 days prior to imaging to potentially induce ovulation in patients with suspected ORS. Alternatively, at the Advanced Gynecologic Surgery Institute in Naperville and Park Ridge, Ill., ovarian stimulation is performed using FSH 300 IUs for 5 days. A finding of cystic structures consistent with ovarian follicles will help narrow the diagnosis.
Use of gonadotropins is superior in that an intact pituitary-ovarian axis is not required. Moreover, monitoring can be in real time; increasing estradiol levels and increasing mass size on ultrasound can be monitored as gonadotropin treatment is rendered. Again, however, negative findings should not necessarily rule out ORS. Unfortunately, there have been no clinical studies looking at the use of controlled ovarian stimulation as a definitive test.
The differential diagnosis includes supernumerary ovary (a rare gynecologic congenital anomaly) and residual ovary syndrome (a condition in which an ovary is intentionally or unintentionally left in place during a hysterectomy, as well as often an intended bilateral oophorectomy, and later causes pain). The latter occurs when surgical anatomy is poor and the surgery is consequently very difficult.