Intraoperative predictors of appendiceal abnormalities in patients with mucinous ovarian neoplasms.

OBJECTIVE: To evaluate intraoperative factors predicting appendiceal pathology during gynecologic oncology surgery for suspected mucinous ovarian neoplasms. METHODS: We conducted a retrospective study on 225 patients with mucinous ovarian neoplasms who underwent surgery for an adnexal mass with concurrent appendectomy between 2000 and 2018. Regression analyses were used to evaluate intraoperative factors, such as frozen section of the ovarian mass and surgeon's impression of the appendix in predicting appendiceal pathology. RESULTS: Most patients (77.8%) had a normal appendix on final pathology. Abnormal appendix cases (n = 26) included: metastasis from high-grade adenocarcinoma of the ovary (n = 1), neuroendocrine tumor of the appendix (n = 4), and low-grade appendiceal mucinous neoplasms (n = 26; 23 associated with a mucinous ovarian adenocarcinoma, 2 with a benign mucinous ovarian cystadenoma, and 1 with a borderline mucinous ovarian tumor). Combining normal intraoperative appearance of the appendix with benign or borderline frozen section yielded a negative predictive value of 85.1%, with 14.9% of patients being misclassified, and 6.0% having a neuroendocrine tumor or low-grade appendiceal neoplasm. CONCLUSION: Benign or borderline frozen section of an ovarian mucinous neoplasm and normal appearing appendix have limited predictive value for appendiceal pathology. Appendectomy with removal of the mesoappendix should be considered in all cases of mucinous ovarian neoplasm, regardless of intraoperative findings.