The Incidence of Unexpected Uterine Malignancy in Women Undergoing Hysterectomy for a Benign Condition: A National Population-Based Study

Background Potential risks associated with using a laparoscopic power morcellator have been reported in terms of the intraperitoneal seeding of benign and malignant diseases; therefore, knowing the precise incidence of unexpected uterine malignancy (UUM) would have clinically significant value. Objective The aim of this study was to investigate the incidence of UUM after a hysterectomy for benign conditions. Methods We analyzed the national inpatient sample data that were extracted by a stratified random sampling (sex and age) method from the Korean National Health Insurance Database between 1 January 2010 and 31 December 2012. Results Among 1,878,507 women treated during the study period, 12,850 women who underwent a hysterectomy for benign conditions were enrolled in this study. The mean age of these women was 47.22 ± 7.07 years. A laparotomic or laparoscopic hysterectomy was performed in 6623 and 6227 women, respectively, and UUM after hysterectomy was diagnosed in 24 women. No significant difference in the incidence of UUM was noted between the laparotomic and laparoscopic cases [laparotomy, 15 (0.23 %); laparoscopy, 9 (0.14 %); p = 0.28]. The incidence of UUM after hysterectomy was 0.19 % [confidence interval (CI) 0.11–0.26 %]; the incidence of unsuspected endometrial cancer after hysterectomy was 0.12 % (CI 0.06–0.19 %); and the incidence of UUM other than endometrial cancer after hysterectomy was 0.06 % (CI 0.02–0.11 %). Conclusion This study shows that the incidence of UUM diagnosed after a hysterectomy for benign conditions was low, but has clinical significance with regard to the potential dissemination of UUM.