Ovarian Remnant Syndrome (ORS) is a complication following an oophorectomy, the surgical removal of one or both ovaries. The syndrome occurs when a small amount of ovarian tissue is unintentionally left behind in the pelvic cavity. This retained tissue remains biologically active, continuing to function, produce hormones, and potentially cause significant patient discomfort. The existence of this functional tissue, often leading to pain or a mass, challenges patients who believed they had undergone a definitive surgical procedure.
Defining Ovarian Remnant Syndrome
Ovarian Remnant Syndrome is characterized by the presence of functional residual ovarian tissue, meaning it is metabolically active and capable of producing reproductive hormones such as estrogen and progesterone. The original intent of the oophorectomy is to eliminate this hormonal function, often to treat hormone-dependent conditions or prevent cancer risk. When a remnant is present, it can continue the cyclical processes of the ovary, including the development of follicles and the formation of cysts.
The persistence of hormonal activity differentiates ORS from simple residual ovarian tissue that is non-functional and asymptomatic. The functional remnant drives symptoms, causing cyclical changes, inflammation, and pain within the pelvis. This retained tissue is often microscopic at the time of surgery and may only grow or become symptomatic months or years later. The remnant tissue can become embedded in scar tissue or adhere to surrounding organs, complicating its eventual identification and removal.
Prevalence and Contributing Factors
Ovarian Remnant Syndrome is considered a rare complication, occurring in less than 1% of women who undergo a bilateral salpingo-oophorectomy (BSO), with or without a hysterectomy. While the exact incidence is difficult to determine due to limited large-scale studies, the condition is a recognized, uncommon complication of gynecologic surgery. Its infrequent occurrence means that clinicians may not immediately consider it when a patient presents with post-surgical pelvic pain.
Several factors increase the likelihood that ovarian tissue will be left behind during the initial surgery. A primary contributing element is the presence of dense pelvic adhesions, which are bands of scar tissue that form between organs following previous surgeries, infection, or disease. These adhesions obscure the normal anatomical planes, making it technically difficult for the surgeon to clearly identify and completely remove the entire ovarian structure.
Pre-existing conditions commonly lead to the formation of severe adhesions. These include severe endometriosis and pelvic inflammatory disease (PID), both of which cause significant inflammation and scarring in the pelvic cavity. When ovarian tissue is firmly embedded within this thick scar tissue, attempts to dissect and remove the ovary can inadvertently leave behind small, viable fragments. Other contributing factors involve intraoperative bleeding, which limits the surgeon’s visibility, and unusual anatomical variations that position the ovary in a location hard to access fully.
Recognizing the Symptoms
The clinical presentation of Ovarian Remnant Syndrome typically involves the return of symptoms the oophorectomy was intended to treat, or the development of new, persistent discomfort. The most common symptom is chronic or cyclical pelvic pain, ranging from a dull ache to severe episodes. This pain stems from the retained tissue continuing to function, leading to the formation of small, hormone-producing cysts that can rupture or bleed.
Patients may also notice a palpable mass or swelling in the pelvis, corresponding to a functional ovarian cyst forming on the remnant tissue. Because the tissue is hormonally active, some women experience symptoms aligning with hormonal fluctuation, such as painful intercourse (dyspareunia) or discomfort during urination or bowel movements. A strong indicator of ORS is the absence of expected menopausal symptoms following a bilateral oophorectomy in a patient not receiving hormone replacement therapy.
Diagnosis and Management
Diagnosing Ovarian Remnant Syndrome begins with a detailed review of the patient’s medical history, noting the onset of symptoms relative to the prior oophorectomy. The presence of chronic pelvic pain and a pelvic mass in a patient who should be surgically menopausal raises strong suspicion for ORS. Imaging studies are then employed to confirm the presence of the retained tissue.
Pelvic ultrasound is the initial imaging modality to visualize any mass or cyst in the pelvic area. However, a Computed Tomography (CT) scan or Magnetic Resonance Imaging (MRI) may be necessary to better define the remnant’s location, especially when obscured by scar tissue. Hormonal blood tests, particularly those measuring estradiol and Follicle-Stimulating Hormone (FSH), are also helpful; a patient with ORS may show persistent estrogen production when they should instead have very low estrogen and very high FSH levels.
The definitive treatment for Ovarian Remnant Syndrome is surgical excision to remove the remaining functional ovarian tissue. This procedure is complex because the remnant is typically encased in the same dense scar tissue that caused the problem initially. Surgeons must proceed with caution, often using specialized techniques, to dissect the tissue from surrounding structures like the bowel or bladder. While surgical removal is the optimal approach, medical management using hormonal agents to suppress the remnant’s activity may be attempted to alleviate symptoms in patients who cannot undergo or refuse repeat surgery.