Adnexal masses are a common gynecologic finding. When small, they are often asymptomatic but larger masses can cause bulk symptoms such as pressure, bloating, and early satiety. Adnexal masses are more likely to be malignant when identified in post-menopausal women compared to younger patients. Providers should consider imaging findings such as size, septations, internal blood flow, and papillary projections in the adnexal masses when conducting surgical planning and when deciding if a general gynecologist or oncologist should perform the surgery. Sometimes despite low pre-operative concerns for malignancy and reassuring intraoperative frozen pathology, final pathology may result with malignancy.

A 32-year-old nulliparous female presented to the emergency room reporting increasing abdominal fullness and discomfort. A computed tomography (CT) scan identified a 34 × 16 × 26-cm fluid filled cystic lesion likely arising from the left adnexa with a few thin septations (Figure 1 and Figure 2). There was mild ascites without peritoneal thickening or nodularity.

The gynecology service was consulted. The patient further described abdominal pressure worsening over the past four months. She denied changes in bowel or urinary function, appetite, weight, or night sweats. She had not been sexually active in three years. She reported regular monthly menses and denied any pertinent medical, surgical, or family history. Her social history was notable for being a Chinese immigrant who did not have health concerns requiring medical attention since arriving in the United States. A large mass was palpable below her ribcage both on bimanual pelvic and abdominal exams. Since the patient was stable, she was referred for outpatient follow-up with gynecologic oncology given the size of the mass.

At her initial appointment with gynecologic oncology, the imaging and normal tumor markers cancer antigen 125 (CA-125) 35 U/mL, carbohydrate antigen 19-9 (CA 19-9) 22 U/mL, lactate dehydrogenase (LDH) 193 U/L, alpha fetoprotein (AFP) 2.9 ng/mL, inhibin B 45 pg/mL were reviewed. Given the normal tumor markers and the simple fluid filled cyst, the risk of cancer was deemed to be low. She was specifically counseled on the risk of upstaging if cancer was found including the risk of spillage. The decision was made to attempt a mini-laparotomy with drainage of the simple appearing cystic fluid followed by laparoscopic resection of abnormal mass. The patient strongly desired future fertility and wanted fertility sparing surgical staging even if cancer was found.

During surgery, a 6-cm supraumbilical vertical incision was made. Two purse string sutures were placed through the cyst wall with 2-0 vicryl without rupturing the mass. A 3-mm incision was made through the cyst wall, the suction was placed in the mass, and the purse string stitches were tightened around the suction to limit the fluid from leaking into the abdomen. Approximately 9 liters of clear fluid was drained. An additional cyst within this mass was palpable and was penetrated with the suction with an additional liter of brown fluid drained. The purse-string suture was then tied down after removal of suction. The cyst was then placed back into the abdomen and the fascial incision was partially closed with 0-vicryl on a UR-6 needle. A 12-mm balloon port was then placed directly through the open portion of the incision. Right and left lateral 5-mm accessory ports were then placed under direct visualization. The cyst was found to be arising from the left ovary with a dilated left fallopian tube. The left peritoneum lateral to the infundibulopelvic ligament was entered and dissected to visualize the left ureter. The left tube and ovary were then removed in the usual fashion with the Ligasure device.

The supraumbilical port was removed. The mass was elevated to the level of the anterior abdominal wall and removed through the laparotomy incision after some extension to accommodate the residual mass intact. The mass was sent to pathology for frozen section. Some fluid was noted in the cul-de-sac during laparoscopy. Omentum and bowel were inspected without evidence of disease. Her remaining pelvic organs were unremarkable. The vertical fascial incision was then closed with a running stitch of 0-vicryl on a UR-6 needle.

Frozen section returned as mucinous cystadenoma with some areas of atypia but unable to determine the percentage of atypical tissue. Surgical staging was not performed given no obvious evidence of malignancy. The patient was discharged home on post-operative day 1 when she was meeting post-operative milestones.

Final pathology then resulted with Grade 2 mucinous adenocarcinoma of the ovary with an unremarkable fallopian tube. Given a final diagnosis of mucinous carcinoma with possible surgical spillage of fluid in the pelvis, the decision was made to perform a second surgical staging procedure.

The next month, she underwent an uncomplicated diagnostic laparoscopy, omentectomy, appendectomy, peritoneal biopsies, pelvic lymph node dissection, and pelvic washings, all of which were negative for carcinoma. The periaortic lymph nodes were evaluated transperitoneally. There were no enlarged lymph nodes and minimal lymphatic tissue was seen in the pelvis. The decision was made not to perform periaortic lymph node dissection in the context of low incidence of lymphatic involvement with mucinous cancers. She was subsequently noted to have Grade 2, Stage 1C1 disease given the possible intra-operative spill. She has since received 3 cycles of carboplatin/paclitaxel and is doing well without evidence of recurrence 1 year after surgery. She has not yet attempted pregnancy.

Our organizational Institutional Review Board judged that this case report did not require their review. Patient consent was obtained to present her case in the literature.

Decision for incision

The patient was originally counseled to undergo an exploratory laparotomy by her gynecologic oncologic surgeon, in part due to the large size of the mass. However, she strongly desired a minimally invasive surgery given her lack of social support to help her during the recovery process and her desire to return to work within a few weeks. Her CT showed a simple fluid containing cyst with few thin septations and did not indicate any solid areas or any metastatic disease. Given the variety of reassuring findings, the risk of cancer was deemed to be low. The patient was educated about the risk of upstaging if cancer was found, including the risk of spillage. She was then consented for a mini-laparotomy with drainage of the cyst. Even though the mass was found to be malignant on final pathology, a mini laparotomy was a reasonable option to pursue based on the low concern for cancer and the patient’s strong preference for minimally invasive surgery. During pre-operative counseling on route of surgery, gynecologists should remember that early stage ovarian cancer can be non-specific on imaging, microscopic metastases may not be visible, and cancer markers can be normal.

As per National Comprehensive Cancer Network guidelines for Stage 1C1 disease, both observation and chemotherapy were reasonable [1]. Given her cancer showed expansile and infiltrative features, she was recommended to proceed with chemotherapy [2].

False negative frozen section

Surgeons often rely on intra-operative frozen section pathology to decide whether cancer surgical staging should be performed during an operation. In this case, the rapid frozen pathology did not suggest malignancy, so the patient did not have staging performed during her initial operation. However, had the frozen section accurately reflected malignancy, she could have had surgical staging during her initial operation and been spared a second surgery. It is important for gynecologists to be aware of the accuracy of frozen sections when performing surgery for adnexal masses.

A 2016 Cochrane Review evaluated ovarian frozen section pathology compared to the permanent paraffin section as the standard reference [3]. When a positive test was defined as invasive cancer and a negative test as either a borderline or benign tumor, the average specificity was 90.0% and the average specificity was 99.5%. When a positive test was defined as either invasive cancer or borderline and a negative test as benign tumor, the average sensitivity was 96.5% and the average specificity was 89.5%. In general, the review noted that if a frozen section showed a benign or invasive cancer, the final diagnosis was consistent 94% and 99% of the time respectively. If a frozen section showed a borderline tumor, 21% of the time the final diagnosis would be invasive cancer, indicating less accuracy in borderline tumor diagnosis. Based on this literature, surgeons can have high confidence in the accuracy of frozen pathology indicating either benign tumors or invasive cancer while recognizing that 6% of the time, the initial benign pathology may be incorrect.

The accuracy of frozen section pathology may be lower in children than adults, as suggested by a Children’s Oncology Group study of patients up to age 20 with malignant ovarian germ cell tumors which found that intra-operative frozen section was incorrect in 38.3% of patients [4].

Although the accuracy of intra-operative frozen pathology is generally high, gynecologists should be aware of discordance rates between rapid frozen and final pathology reports and counsel patients of this possibility. Patients with adnexal masses should always be educated about the risk of malignancy and the possibility of requiring a second surgery if the first is performed by a non-oncologist and/or if additional staging surgery is recommended based on final pathology report.