Occult uterine leiomyosarcoma in women undergoing abdominal and minimally invasive surgeries for myomas.

Objectives: To estimate (i) the incidence of occult uterine leiomyosarcoma (LMS) in patients operated on for presumedmyomas, and (ii) the proportion of occult LMS to preoperatively diagnosed LMS in a tertiary center.

Material And Methods: An Institutional Review Board-approved retrospective cohort study was performed. The electronicdatabase of 30,476 patients was searched for women who had undergone surgery due to presumed myomas (N = 2675) as well as those with uterine LMS recognized via histology (N = 10) between January 2010 and December 2016.

Results: Six of the 2675 treated women had occult LMS (incidence 1:446; 0.002; CI 0.0-0.013), and one underwent power morcellation (incidence 1:951; 0.001; CI 0.0-0.006). Parallel searching revealed that 6 of the 10 cases (60%) with uterine LMS recognized via histology were diagnosed postoperatively, whereas 4 of the 10 (40%) were diagnosed preoperatively. The incidence of LMS morcellation during laparoscopy was 1:951 and, when all MIS cases were included, 1:1178. The patient who underwent LMS morcellation was operated in the general surgery ward 5 years after laparoscopy (omental recurrence).

Conclusions: These results are similar to the first and recent conservative FDA estimations, but two-times lower for procedures with laparoscopic morcellation and all MIS procedures than for abdominal. Because above half of LMS may be recognized after surgery, the risk of occult LMS and the delay of targeted surgical treatment should be included in all informed consent forms for conservative management of presumed myomas without histology.