[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Female genital tract](https://durgical.com/en/general-pathology/areas/female-genital/) › Mucinous ovarian tumours # Mucinous ovarian tumours - Lesion Mucinous ovarian tumours can be huge sticky cysts, mostly benign. A mucinous tumour in both ovaries is more often a metastasis from the gut. Updated Nov 12, 2026 ## Key points - Cystadenoma: large multiloculated cyst filled with sticky mucin, lined by tall non-ciliated mucinous cells. - Borderline tumour: stratified mucinous epithelium with atypia, no destructive invasion. - Carcinoma: confluent or infiltrative glands; KRAS early, TP53 and ERBB2 amplification later. - Primary tumours are usually unilateral and large; bilateral, small, surface-involving or nodular tumours suggest metastasis. - Pseudomyxoma peritonei: mucinous ascites from a low-grade appendiceal mucinous neoplasm, with secondary ovarian involvement. ## What it is Mucinous ovarian tumours are lined by mucin-producing cells, usually of intestinal type. Most are benign cystadenomas, which can grow very large and are multiloculated; borderline tumours and primary carcinomas are less common and usually unilateral. KRAS mutation is the earliest step. Because metastases from the gastrointestinal tract, especially the appendix, colon, stomach and pancreas, can look like primary mucinous tumours, bilateral or small tumours with surface disease are presumed metastatic until proven otherwise. Pseudomyxoma peritonei nearly always comes from the appendix. ## Structure - Gross: a smooth-surfaced, often enormous, multiloculated cyst with thick mucoid contents. - Lining: a single layer of columnar mucinous cells, sometimes with goblet and Paneth cells (intestinal type). - Borderline and malignant tumours show papillary and glandular crowding; carcinoma shows stromal invasion. - Mucinous tumours can arise in a teratoma or alongside a Brenner tumour. ## Step by step - A KRAS mutation in surface or teratoma-derived epithelium starts a benign mucinous cyst. - Further mutations produce a borderline tumour. - TP53 mutation or ERBB2 amplification accompanies progression to invasive carcinoma. - Rupture spills mucin and cells; true pseudomyxoma, however, is usually appendiceal in origin. ## Markers - CK7 positive (ovarian primary) - CK20 and SATB2 (favour colorectal or appendiceal origin) - PAX8 often negative ## Clinical notes - Present as a large abdominal mass or swelling; CEA and CA 19-9 may be raised more than CA-125. - In any mucinous ovarian tumour, the appendix and gastrointestinal tract are examined to exclude a primary there. ## Memory aid One big sticky ovary is probably home-grown; two smaller sticky ovaries are probably visitors from the gut. ## Test yourself Think of the answer, then tap the question to see it. ## Which features suggest that a mucinous ovarian tumour is a metastasis? Bilaterality, smaller size, surface involvement, nodular growth and an intestinal immunoprofile such as CK20 and SATB2 positivity. ## Where does pseudomyxoma peritonei usually come from? From a low-grade mucinous neoplasm of the appendix. ## Which mutation is an early event in ovarian mucinous tumours? KRAS. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/general-pathology/mucinous-ovarian-tumours/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Elsewhere in DurgiPedia - [Tumour markers: principles of use](https://durgical.com/en/biochemistry/topics/tumour-markers-principles-of-use/) ## Connections ## Related 8 - [Metastases to the ovary](https://durgical.com/en/general-pathology/metastases-to-the-ovary/) - [Ovarian tumours: classification](https://durgical.com/en/general-pathology/ovarian-tumours-classification/) - [Low-grade serous ovarian tumours](https://durgical.com/en/general-pathology/low-grade-serous-ovarian-tumours/) - [Ovarian teratomas](https://durgical.com/en/general-pathology/ovarian-teratomas/) - [Tumours of the appendix](https://durgical.com/en/general-pathology/tumours-of-the-appendix/) - [Metaplasia](https://durgical.com/en/general-pathology/metaplasia/) - [Benign vs malignant tumours: the comparison table](https://durgical.com/en/general-pathology/benign-vs-malignant-tumours-the-comparison-table/) - [Pathways of spread and the usual metastatic sites](https://durgical.com/en/general-pathology/pathways-of-spread-and-the-usual-metastatic-sites/) ## Related conditions 3 - [Ovarian cancer](https://durgical.com/en/conditions/ovarian-cancer/) - [Ovarian cyst](https://durgical.com/en/conditions/ovarian-cyst/) - [Colorectal cancer](https://durgical.com/en/conditions/colorectal-cancer/) [← All of general pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Epithelial Ovarian Cancer](https://www.ncbi.nlm.nih.gov/books/NBK567760/) (StatPearls (NCBI Bookshelf), 2026); [Ovarian Epithelial, Fallopian Tube, and Primary Peritoneal Cancer Treatment (PDQ®)–Health Professional Version](https://www.cancer.gov/types/ovarian/hp/ovarian-epithelial-treatment-pdq) (National Cancer Institute, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/general-pathology/mucinous-ovarian-tumours/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/mucinous-ovarian-tumours/