Ovarian cancer (OC) is the most lethal gynecological malignancy. Epithelial OC is the most common histological type, with high-grade serous carcinoma (HGSC) being the most common subtype, accounting for more than 70 % of OC cases in general [1]. On the other hand, primary mucinous OC (MOC) is a relatively rare subtype of epithelial OC, accounting for roughly 1 %-3% of all cases of OC. Previously, the prevalence of MOC was overestimated as around 10 % of epithelial OC due to confusion with metast…