Analysis of malignant and borderline ovarian tumors, comparing pre- and post-laparoscopic diagnoses

Purpose: To evaluate the incidence, character, and prognosis of ovarian tumors diagnosed as benign before laparoscopic surgery but identified as malignant or of borderline malignancy by postoperative histopathology.Subjects: Of 1,066 laparoscopic ovarian tumor resections at Tohoku Kosai Hospital from April 2001 to May 2010, a total of 22 patients were postoperatively confirmed as having overt or borderline malignancies. Methods: For this patient subset, the following factors were analyzed: postsurgical histopathology, patient age, tumor size, solid tumor component, CA125 and CA19-9 markers, laparoscopic technique, tumor capsule status, adjunctive therapy, and prognosis.Results: The rate of preoperative diagnostic error was 2.2% (22/1,066). Of the 22 misinterpreted tumors, five were clearly malignant, and 17 were of borderline malignant potential. Although no specific tendencies were evident, based on analysis of preoperative features, malignant lesions were more likely in older patients or in those with large sized cysts. For two of the five patients with malignancies, definitive cancer surgery was performed, followed by chemotherapy, while the other three received chemotherapy alone. Three of the 17 patients with borderline malignancy also opted for surgery. Endometrial carcinoma was found in one patient with malignancy, and recurrent mucinous cysts occurred in two patients with borderline tumors, but the long-term prognosis for these patients in close follow-up was fairly good.Conclusion: Preoperative misdiagnosis of ovarian malignancies may be unavoidable, despite thorough assessment. However, even with laparoscopic resection, the prognosis of such tumors is not poor, given adequate adjunctive therapy and/or careful clinical follow-up.