Gynecologic Oncology Consult

Approach to the asymptomatic adnexal mass: When to operate, refer, or observe


Adnexal masses are common findings in women. While the decision to operate on symptomatic adnexal masses is straightforward, the decision-making process for asymptomatic masses is more complicated. Here we address how to approach an asymptomatic adnexal mass, including how to decide when to operate, when to refer, or how to monitor.

Dr. Lisa Jackson-Moore

Dr. Lisa Jackson-Moore

Approximately 200,000 women in the United States undergo surgery for a pelvic mass annually, yet only 21,290 are ultimately found to have ovarian cancer.1 Therefore, only approximately 1 in 10 women in the United States who have surgery for adnexal masses have an underlying malignancy.

It is important to minimize the number of surgeries for benign, asymptomatic adnexal masses because complications are reported in 2%-15% of surgeries for adnexal masses and these can range from minimal to devastating.1 In addition, unnecessary surgery is associated with a burden of cost to the health care system. Therefore, there is a paradigm shift in the management of asymptomatic adnexal masses trending toward surveillance of any masses that are likely to be benign. What becomes critical in this approach is the ability to accurately classify these masses preoperatively.

Determining the malignant potential of a mass

Guidance is provided by the ACOG Practice Bulletin Number 174, which was published in 2016: “Evaluation and Management of Adnexal Masses.”2 These guidelines remind clinicians that:

  • Most adnexal masses are benign, even in postmenopausal patients.
  • The recommended imaging modality is quality transvaginal ultrasonography with an ultrasonographer accredited through the American Registry of Diagnostic Medical Sonographers.
  • Simple cysts up to 10 cm can be monitored using repeat imaging every 6 months without surgical intervention, even in postmenopausal patients. In prospective studies, no cases of malignancy were diagnosed over 6 years of surveillance and most resolved. Those that persist are likely to be serous cystadenomas.
  • Many benign lesions such as endometriomas and cystic teratomas have characteristic radiologic features. Surgery for these lesions is warranted for large size, symptoms, or growth in size.
  • Ultrasound characteristics of malignant masses include:

1. Cyst size greater than 10 cm

2. Papillary or solid components

3. Septations

4. Internal blood flow on color Doppler.

Dr. Emma C. Rossi is an assistant professor in the division of gynecologic oncology at UNC-Chapel Hill.

Dr. Emma C. Rossi

An international multidisciplinary panel of experts has convened on this topic. The panel defined two approaches to diagnosing asymptomatic adnexal masses based on morphologic features on ultrasound. The first approach was a simple risk assessment stratification profile based on pattern recognition.1 This approach categorizes masses as: almost certainly benign, almost certainly malignant, suspicious for malignancy, or indeterminate. Those that are almost certainly malignant or suspicious for malignant can be referred to a gynecologic oncologist for surgical evaluation. Those that are almost certainly benign can be observed. For those in the indeterminate group, further evaluation with MRI, serial ultrasound, tumor marker assessment (for example, CA 125), or application of risk-prediction models (such as the International Ovarian Tumor Analysis Group’s “simple rules”) can be employed to identify candidates for observation or referral. However, there will remain a portion of patients in whom the masses remain “indeterminate.” These patients are typically treated as though they may be malignant, and referral to an oncology specialist is recommended to help decide whether to proceed with surgery or observation.

An alternative approach that has been proposed is an ultrasound scoring system devised by International Ovarian Tumor Analysis Group. The scoring system uses 10 ultrasound findings that are characteristic of malignant and benign and is designed to characterize masses as either benign or malignant.3 This approach is able to correctly classify 77% of masses. The remaining masses with features that do not fit the “simple rules” are considered potentially malignant and should be referred to an oncology specialist for further decision making.

Decision to operate

After referral to gynecologic oncologists, surgery is not always inevitable, particularly for women with indeterminate masses. The gynecologic oncologist uses a decision-making process that factors in the underlying surgical risks for that patient with the likelihood of malignancy based on the features of the mass. The threshold to operate is higher in women with underlying major comorbidities, such as morbid obesity, complex prior surgical history, or cardiopulmonary disease. Healthier surgical candidates are more likely to be considered for a surgery, even if the suspicion for malignancy is lower. However, low surgical risk does not equate to no surgical risk. Therefore, even in apparently “good” surgical candidates, the suspicion for underlying malignancy needs to be reasonably high in order to justify the cost and risk of surgery in an asymptomatic patient. Sometimes it is patient anxiety and a desire to avoid repeated surveillance that prompts a decision to operate.


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