Guideline No. 404: Initial Investigation and Management of Benign Ovarian Masses



      To provide recommendations for a systematic approach to the initial investigation and management of a benign ovarian mass and facilitate patient referral to a gynaecologic oncologist for management.

      Intended Users

      Obstetricians, gynaecologists, family physicians, internists, nurse practitioners, radiologists, general surgeons, medical students, medical residents, fellows, and other health care providers.

      Target Population

      Women ≥18 years of age presenting for evaluation of an ovarian mass (including simple and unilocular cystic masses, endometriomas, dermoids, fibromas, and hemorrhagic cysts) who are not acutely symptomatic and without known genetic predisposition to ovarian cancer.


      This guideline aims to encourage conservative management and help reduce unnecessary surgery and long-term health complications, maintain fertility, and decrease operative costs and improve overall patient care and outcomes by providing criteria for referral of patients with ultrasound imaging findings suggestive of a malignant mass to a gynaecologic oncologist.


      Databases searched: Medline, Cochrane, and PubMed. Medical terms used: benign asymptomatic and symptomatic ovarian cysts, adnexal masses, oophorectomy, ultrasound diagnosis of cysts, simple ultrasound rules, surgical and medical therapies for cysts, screening for ovarian cancer, ovarian torsion, and menopause. Initial search was completed by 2017 and updated in 2018. Exclusion criteria were malignant ovarian cystic masses, endometriosis therapies, and other adnexal pathologies unrelated to the ovary.

      Validation Methods

      The content and recommendations were drafted and agreed upon by the authors. The Society of Obstetricians and Gynaecologists of Canada's Board of Directors approved the final draft for publication. The quality of evidence was rated using the criteria described in the Grading of Recommendations Assessment, Development and Evaluation methodology framework.

      Benefits, Harms, Costs

      Implementation of the recommendations could reduce costs due to unnecessary surgeries and hospitalizations and reduce lost work days and the risk of loss of fertility, early menopause, and surgical complications.

      SUMMARY STATEMENTS (GRADE ratings in parentheses)

      • 1
        The following ovarian masses typically demonstrate classic benign features on ultrasound: simple or unilocular cystic mass, hemorrhagic cyst, endometrioma, mature cystic teratoma (dermoid), and fibroma (high).
      • 2
        The risk of malignancy for simple ovarian cystic masses is low (<1%) for <10 cm in diameter (high).
      • 3
        Patients with an ovarian mass ≥5 cm in diameter are at increased risk for ovarian torsion (moderate).
      • 4
        Laparoscopy is the recommended approach for surgical management of symptomatic benign ovarian masses because it not only is technically feasible and safe but also provides the advantages of shorter hospital stays, faster recovery times, and less pain and bleeding compared with laparotomy (high).
      • 5
        Comprehensive preoperative evaluation is necessary in order to determine the risk of malignancy of an ovarian mass before deciding on the appropriate surgical management (high).
      • 6
        Electrocautery for hemostasis should be used sparingly in order to reduce the risk of damage to healthy ovarian tissue and minimize adhesion formation (high).

      RECOMMENDATIONS (GRADE ratings in parentheses)

      • 1
        In the asymptomatic patient, masses characterized as benign on ultrasound can be followed initially by repeat ultrasound in 8 to 12 weeks, preferably in the proliferative phase of the menstrual cycle for premenopausal women. Follow-up ultrasound can then be done yearly for masses that remain stable and do not develop malignant features (strong, moderate).
      • 2
        Most asymptomatic masses <10 cm in diameter and characterized as benign can be managed conservatively (strong, high).
      • 3
        If surgery is performed for a symptomatic mass characterized as benign on ultrasound, unilateral or bilateral oophorectomy can be considered for postmenopausal women (strong, low) and ovarian cystectomy can be considered for premenopausal women if technically feasible (strong, low). For perimenopausal women, the decision to perform a cystectomy with a possible salpingectomy versus an oophorectomy should be part of a shared decision-making discussion between the patient and her health care provider (strong, low).
      • 4
        Laparoscopic ovarian cystectomy is the recommended surgical approach for removal of cystic masses, rather than fenestration and aspiration (strong, moderate).
      • 5
        Laparoscopic management should involve examination of the peritoneal surfaces, appendix, upper abdomen, posterior cul-de-sac, and bladder in addition to uterus, tubes, and ovaries for evidence of disease. In addition to pelvic washing for cytology, a biopsy of peritoneal surfaces should be taken for histopathology only if malignancy is suspected (strong, high).
      • 6
        Peritoneal washing for cytology and frozen section for analysis should be undertaken at the time of surgical management of an ovarian mass if there is a suspicion of malignancy. To improve the diagnostic accuracy, specimens should be interpreted by a pathologist with gynaecologic expertise, if resources permit (strong, high).
      • 7
        When pathology results reveal malignancy in an ovarian mass that had originally been presumed benign, comprehensive surgical staging should be performed by a surgeon with expertise in gynaecologic oncology, if resources permit (strong, high).


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