During a cesarean section, should a 10‑cm incidental, asymptomatic, benign‑appearing adnexal mass be left in place and managed postpartum with surveillance rather than removed intraoperatively?

Management of Incidental Adnexal Mass at Cesarean Section

For a 10-cm incidental, asymptomatic, benign-appearing adnexal mass discovered during cesarean section, the mass should be removed intraoperatively rather than left in place, as this approach avoids additional surgical procedures, excludes malignancy definitively, and eliminates the risk of postpartum torsion. 1, 2, 3

Rationale for Intraoperative Removal

Size-Based Risk Assessment

• Masses ≥10 cm require surgical removal due to significantly increased risk of torsion (mean size of masses undergoing torsion is 10 cm) and technical difficulty if delayed 1, 2
• The torsion risk in pregnancy ranges from 3-12% for adnexal masses, with larger masses at highest risk 1
• Obstruction of labor occurs in 3% of cases with cysts >3 cm, making a 10-cm mass particularly problematic 1

Malignancy Exclusion

• Approximately 2% of adnexal masses in pregnancy are malignant, and definitive histopathologic diagnosis cannot be established without surgical removal 1
• Even "benign-appearing" masses on ultrasound can harbor malignancy, as 38-60% of pregnant patients with torsion have normal Doppler flow, demonstrating imaging limitations 1, 4
• In a large series of incidental masses at cesarean section, 5% were malignant despite appearing benign preoperatively 3

Surgical Efficiency and Morbidity Reduction

• Removing the mass at the time of cesarean section avoids a second surgery with additional anesthetic exposure, recovery time, and surgical risks 3
• The abdomen is already open with optimal surgical access, making concurrent removal technically straightforward 3
• Elective surgery (concurrent with cesarean) is safer than emergent surgery (for postpartum torsion), with fetal loss rates of 1% vs 5% and preterm birth rates of 4% vs 12% 1

Intraoperative Decision-Making Algorithm

Proceed with Removal If:

• Mass is ≥10 cm (as in this case) 2
• Mass has any suspicious ultrasound features (irregular solid components, thick septa, ascites, papillary projections) 1, 2
• Patient is asymptomatic but mass persisted throughout pregnancy 1, 2
• Adequate surgical expertise is available 1

Technical Considerations During Cesarean

• Perform ovarian cystectomy rather than oophorectomy when technically feasible to preserve ovarian function 2
• Send frozen section if any concerning features are noted intraoperatively 5
• If frozen section suggests malignancy, close and refer to gynecologic oncology for comprehensive staging rather than attempting definitive surgery 5

Common Pitfalls to Avoid

False Reassurance from "Benign Appearance"

• Ultrasound scoring systems (IOTA, ADNEX) have sensitivities of only 62-92% for malignancy detection in pregnancy 1
• Dermoid cysts (32% of surgical masses in pregnancy) and cystadenomas (19%) appear benign but require removal at this size 1, 2

Deferring to Postpartum Management

• Approximately 70% of masses resolve spontaneously, but this applies primarily to masses <5 cm with simple features 1
• A 10-cm mass has minimal likelihood of spontaneous resolution and high likelihood of requiring surgery regardless 1, 2
• Postpartum torsion risk remains elevated (4-15% recurrence rate if torsion occurs once) 1, 4

Inadequate Surgical Planning

• Do not attempt removal if irregular solid components, matted bowel, or ascites are present—these require formal staging laparotomy by gynecologic oncology 2
• Ensure appropriate surgical expertise is available before proceeding, as inadequate resection may compromise oncologic outcomes if malignancy is present 5

Alternative Approach (Not Recommended for 10-cm Mass)

If the mass were <5 cm with entirely benign features (unilocular, thin-walled, no solid components), postpartum surveillance with ultrasound at 6-8 weeks could be considered 1, 2. However, at 10 cm, the balance of risks strongly favors intraoperative removal given the high torsion risk, low resolution probability, and surgical efficiency of concurrent removal 1, 2, 3.