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.
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.
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.
Elsewhere in DurgiPedia
Connections
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 (StatPearls (NCBI Bookshelf), 2026); Ovarian Epithelial, Fallopian Tube, and Primary Peritoneal Cancer Treatment (PDQ®)–Health Professional Version (National Cancer Institute, 2026).
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Representative model, for educational purposes only.