Ovarian mucinous carcinoma is an invasive malignant ovarian tumor originating from mucin-producing epithelial cells. It accounts for 3-4% of all epithelial ovarian cancers. Typically presents as a very large (>10 cm, mean 15-20 cm), unilateral, multilocular cystic-solid mass. Contains significant solid component, thick irregular septa, and mural nodules. An important clinical challenge is distinguishing primary ovarian mucinous carcinoma from appendiceal or GI-origin metastases — when bilateral involvement or peritoneal mucin is present, GI primary must be strongly considered. CA 19-9 is a more sensitive marker than CA-125.
Age Range
30-60
Peak Age
50
Gender
Female predominant
Prevalence
Uncommon
Mucinous carcinoma may develop through invasive transformation in a mucinous borderline tumor background (borderline → intraepithelial carcinoma → invasive carcinoma) or arise de novo. KRAS mutation is detected at 40-65% rate and is considered an early oncogenic event. HER2 amplification is seen at 15-20% rate and is important in targeted therapy. The large size of the tumor results from mucin accumulation — invasive areas are imaged as solid component and mural nodules. Thick irregular septa reflect areas of stromal invasion and show intense enhancement. The peritoneal dissemination tendency of mucinous carcinoma is lower than serous carcinoma — it shows more local growth. Bilateral involvement is rare in true primary mucinous carcinoma (2-5%), and when bilateral masses are present, metastatic disease (appendix, colon, stomach) should be primarily considered.
Solid nodules originating from the cyst wall or septa of a multilocular cystic mass, showing diffusion restriction on DWI and intense enhancement on contrast sequences. These mural nodules represent the focal point of invasive carcinoma and distinguish it from borderline tumors. When nodule size >1 cm and number >3, probability of invasive carcinoma significantly increases.
Contrast-enhanced CT shows a very large (>10 cm, often >15 cm), unilateral, multilocular cystic-solid mass. Loculations are seen at variable densities (0-30 HU). Solid component and mural nodules show intense enhancement. Thick (>3 mm), irregular septa are present and may coexist with thin septa (mixed septal pattern).
Report Sentence
A very large multilocular cystic-solid mass is identified in the right/left ovarian location with thick irregular septa and intense enhancement of solid components; mucinous carcinoma should be the primary consideration.
T1-weighted MRI shows distinctly variable signal in loculations. Loculations containing protein-rich/thick mucin are hyperintense on T1, while watery mucin-containing loculations are hypointense. This T1 signal variability (MRI equivalent of 'stained-glass' appearance) is characteristic of mucinous tumors. Hemorrhagic areas may also appear T1-hyperintense.
Report Sentence
Distinctly variable signal intensity is observed within loculations on T1-weighted sequences (hypointense to hyperintense), indicating variable mucin concentration consistent with mucinous neoplasm.
Diffusion restriction is seen in mural nodules and solid components on DWI — bright on high b-values, low signal on ADC map. No true diffusion restriction in cystic loculations (T2 shine-through may occur). Mural nodules showing diffusion restriction are the most specific MR finding of invasive carcinoma and distinguish it from borderline.
Report Sentence
Diffusion restriction is observed in mural nodules and solid components on DWI with low ADC values, consistent with invasive mucinous carcinoma.
US shows solid component and mural nodules within a very large, multilocular cystic mass. Loculations appear at variable echogenicity ('stained-glass'). Thick irregular septa are present. Unlike borderline, significant solid components and mural nodules raise suspicion for malignancy.
Report Sentence
Mural nodules and solid components are identified within a very large multilocular cystic mass on US; mucinous malignancy should be the primary consideration.
Doppler US shows markedly increased vascular flows in mural nodules and solid components. Low-resistance arterial flows (RI <0.5) favor malignancy. Septa may also show increased vascular flow. This Doppler finding is distinctly different from the limited vascular flow in borderline.
Report Sentence
Doppler examination demonstrates increased vascular flows and low-resistance arterial flow pattern in mural nodules and solid components, favoring malignancy.
Contrast-enhanced MRI shows intense, early enhancement of solid component and mural nodules. Thick irregular septa also demonstrate significant enhancement. No enhancement in cystic loculations. This enhancement pattern — intense solid + enhancing thick septa + non-enhancing cystic areas — is characteristic of invasive mucinous carcinoma.
Report Sentence
Intense early enhancement of solid component and mural nodules and significant enhancement of thick irregular septa are observed on contrast-enhanced MRI, consistent with invasive mucinous carcinoma.
Criteria
Characterized by pushing of broad stroma with preserved stromal-epithelial border, well-demarcated invasion pattern. Has better prognosis.
Distinct Features
More well-demarcated solid component on imaging, less aggressive appearance. Still, size and presence of mural nodules distinguish from borderline. 5-year survival >80%.
Criteria
Stromal destruction, irregular-bordered invasion, desmoplastic stromal reaction. Has worse prognosis.
Distinct Features
More irregular-bordered solid component on imaging, more aggressive appearance. Peripheral invasion findings more prominent. 5-year survival 40-60%.
Criteria
When bilateral ovarian involvement, small ovarian size (<10 cm), surface implants, peritoneal mucin/pseudomyxoma peritonei, and primary tumor in appendix or GI is present, metastatic disease should be primarily considered.
Distinct Features
CK7-/CK20+ (intestinal immune profile), bilateral and relatively small masses, presence of mucocele/tumor in appendix, peritoneal mucin accumulation. In primary ovarian mucinous carcinoma, CK7+/CK20- ratio is higher.
Distinguishing Feature
In mucinous borderline, septa are thin (<3 mm) and regular, while in carcinoma they are thick (>3 mm) and irregular. Mural nodules and significant solid component are present in carcinoma. No diffusion restriction in borderline on DWI while marked restriction is seen in solid areas in carcinoma.
Distinguishing Feature
Serous carcinoma is bilateral, more solid, with more prominent peritoneal dissemination (omental cake, ascites). Mucinous carcinoma is unilateral, larger, predominantly cystic with rare peritoneal dissemination. CA-125 is very high in serous carcinoma; CA 19-9 is more sensitive in mucinous carcinoma.
Distinguishing Feature
Metastasis (especially from appendix/colorectal/gastric origin) is bilateral, relatively small (<10 cm), with surface implants and peritoneal mucin. Mucocele or primary tumor in appendix should be searched. Primary mucinous carcinoma is large (>10 cm) and unilateral.
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
specialist-referralTreatment is surgical — TAH-BSO + omentectomy + appendectomy (mandatory in mucinous tumors) + peritoneal staging. Primary mucinous carcinoma in stage I has good prognosis (5-year survival >85%). In advanced stages (rare), platinum-based chemotherapy is added but response is lower than serous carcinoma. Trastuzumab may be considered with HER2 amplification. Critical decision: when bilateral involvement or peritoneal mucin is present, GI primary must be excluded — appendectomy + colonoscopy + upper GI endoscopy are recommended. Urgent referral to gynecologic oncology is required.
Ovarian mucinous carcinoma is usually diagnosed at early stage (unilateral, confined). Prognosis is better than serous carcinoma. Appendiceal primary should be excluded in pseudomyxoma peritonei. Treatment is surgery + chemotherapy.