Introduction/Background Primary mucinous ovarian carcinoma (MOC) is a rare type of epithelial ovarian cancer. Therefore, we aimed to investigate clinic-pathological characteristics and prognosis of primary MOC.

Methodology The clinical data of 17 patients with primary ovarian mucinous adenocarcinoma out of 703 patients with ovarian cancer (2.41%) from September 2018 to November 2023 in Shatby Maternity Hospital Affiliated to Alexandria University were retrospectively analyzed. The pathological sections were reviewed, and the clinicopathological characteristics were analyzed by immunohistochemical staining.

Results The average age of 17 patients was 45.2 (16–70). Tumour sizes ranged from 8 to 37 cm, averaging 17.5 cm. The unilateral ovarian tumour was 82.3%. and the bilateral was 17.4%. Immunohistochemical result showed that the positive rates of cytokeratin (CK) 7, CK20 and tail-type homeobox gene (CDX) 2 were 100.0%, 70.5% and 52.9%; the positive rates of paired box gene (PAX) 8 and special AT-rich sequence-binding protein (SATB) 2 were 17.6% and 11.7%. According to the 2014 FIGO classification of ovarian cancer, 10 case identified as stage I, 4 as stage II, 2 as stage III, and 1 as stage IV. Patients were followed for 3–48 months, with an average of 26 months. Only 7 cases(6 cases in FIGO stage I and 1 stage II) had no recurrence or metastasis. Three cases (1 in stage I, 1 in stage II and 1 in stage III) had recurrence within 2 years, with 2 cases died within 5 years. Five cases (2 stag I and 3 stage II) were lost to follow-up.

Conclusion Immunohistochemical result shows that CK7 is always positive, the expressions of CK20 and CDX2 are different degree, and SATB2 and PAX-8 are mostly negative. Prognosis is closely related with FIGO stage, and the patients with FIGO I stage have good prognoses, III and IV stage have poor prognoses.

Disclosures The authors declare no conflict of interest.

This research received no external funding.