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Ovarian Remnant Syndrome (or…when you have had your ovaries removed and they find one on ultrasound!)

By Ken Sinervo, MD, MSc, FRCSC, ACGE, Medical Director

Another potential source of pain in women that have had a hysterectomy with removal of one or both ovaries is a condition called Ovarian Remnant Syndrome.  Typically, the patient presents with lower quadrant pain that localizes to one side or the other.  The pain may be quite severe.  It may resolve spontaneously or persist or be cyclical recurring monthly.

The key to diagnosis is seeing a mass on ultrasound, CT scan or MRI which is cystic and localizes to the areas of the ovary.  Patients will often say they can’t have a cyst or ovarian tissue since they have had their ovaries removed.  The doctor will often echo similar sentiments.  When a mass consistent with an ovarian cyst is seen post-oophorectomy (removal of the ovary), certain tests may help to confirm that this is ovarian in nature.  If you are taking hormone replacement, it could be stopped for a month and if there are no hot flashes or other symptoms of menopause, it is suggestive that the cyst is related to an ovarian remnant.

You can also have your estrogen levels tested when not on hormone replacement therapy and your estrogen levels may be higher than normal for someone not on hormone replacement therapy (typically >30 pg/mL if there is ovarian tissue present).  As well, a blood test called FSH or follicle stimulating hormone will also be lower than normal for a menopausal woman.  FSH is usually greater than 30 when you are in menopause (your brain is trying to stimulate the ovaries but does not see the rise in estrogen that is seen when ovaries are present, so it produces more FSH to stimulate the ovaries to try to get the estrogen elevated).  When you are young and your ovaries are intact and fertility is viable, the FSH level is usually less than 10.  So, anyone who has had a hysterectomy with removal of both ovaries should have a level of FSH higher than 30.  If it is less than 30, you likely have an ovarian remnant.

How do ovarian remnants occur?  New ovarian tissue does not grow.  Ovarian remnants occur when the ovary is bluntly dissected from the pelvic sidewall when it is adhered or scarred down to the pelvic sidewall.  This scarring is usually the result of endometriosis which causes inflammation, and the result of that inflammation is the formation of adhesions.  These adhesions can often be very dense and difficult to separate the ovary from the pelvic sidewall or bowel to which it may be scarred to.  Often, the gynecologist will use instruments or their hands if done through a large incision, but they are leaving small portions of the ovary on the pelvic sidewall.  This little piece of ovarian tissue can generate its own blood supply and respond like a normal ovary would to stimulation by FSH and produce hormones and create ovarian cysts.  We prevent the occurrence of ovarian remnants by carefully removing the tissue on the pelvic sidewall as well, since there is usually endo on that pelvic sidewall as well and we want to minimize the recurrence of disease.  Most doctors do not do this and the results are not only the ovarian remnant, but also endometriosis in the area as well.  Pelvic pain will result months or even years later.

We have treated more than one hundred individuals with ovarian remnants.  All have been successfully managed laparoscopically with no recurrence of the ovarian remnants.  We have never had an ovarian remnant occur in a patient that we have removed an ovary or performed a hysterectomy with removal of one or both ovaries.  We did have one patient that had a second remnant in a different location, since ovarian tissue was left in different areas of the pelvis and only one of the remnants was activated during the initial surgery.

Ovarian remnant surgery can be quite challenging and if your doctor has not performed any of these procedures, there is increased risk of complications to the patient, and increased likelihood of recurrent ovarian remnants.  We had one patient that had two additional surgeries to the remnant before having surgery at the CEC to finally completely remove the remnant.  The reason that these surgeries are difficult has to do with the fact that there can be a lot of scarring and adhesions which makes dissection difficult, and the bowel may also be densely adhered to the remnant and many gynecologists are reluctant to dissect these dense adhesions of the bowel due to the risk of injury to the bowel.  We routinely perform delicate dissections of the bowel every week because of the severe nature of the endometriosis that we see, including patients with stage IV endometriosis with bowel involvement.  This unique skill set allows us to comfortably restore anatomy to normal and dissect the remnants off the bowel.

Another factor that makes these difficult for the average surgeon is that the remnant is usually scarred to the pelvic sidewall, and the ureter and large pelvic vessels run in this area.  Many gynecologists are reluctant to treat these due to concern about injury to these structures.  Endometriosis often affects the area under the ovary or the pelvic sidewall (in fact between 30-40% of patients have endo in these locations).  We excise endo in these areas almost daily, and routinely dissect out the ureter and pelvic vessels so that all the disease can be safely and successfully removed.  This practice of working in the retroperitoneal space (area occupied by the ureters and pelvic vessels) allows us to comfortably dissect ovarian remnants from these delicate structures with minimal risk.

If you have recurrent pelvic pain after hysterectomy for your endometriosis or other conditions in which the ovaries may have been scarred to other structures, it would be worthwhile to have an ultrasound and blood work (estrogen and FSH levels) to rule out ovarian remnant.  If you have a history of endometriosis and have recurrent pain following a hysterectomy and do not have a possible remnant, there is always the possibility of persistent endometriosis from under-treatment of that endometriosis at the time of your hysterectomy.

If you have pelvic pain, we can likely help. Please ask questions!