Received: 4 January 2022
Accepted: 18 March 2022
First Online: 23 March 2022
: Clearance was obtained from Research and Ethics Review Committee, Hokkaido Cancer Center for the publication of this report.
: Written informed consent was obtained from all the patients for publication.
: The authors declare that they have no competing interests.
: This study was a report of only three cases in a single center, therefore, was not able to show the proportion of metastatic or primary cancer among the giant ovarian tumor.