ovarian mucinous tumours

Ovarian mucinous tumors are a subgroup of ovarian epithelial tumors. They represent 10-15% of all ovarian tumors and ~10% of all malignant ovarian tumors. They are subdivided according to their malignant potential and clinical behavior into:

Clinical presentation

Benign mucinous tumors tend to affect women 20-40 years old, whereas borderline and malignant tumors tend to occur in a slightly older age range (40-50 years of age) ,

Pathology

On histology they show multiple cysts lined by mucinous epithelium, often resembling gastrointestinal-type epithelium . KRAS mutations are a common feature.

Subtypes

Mucinous ovarian tumors can be broadly subclassified into three main subgroups:

Radiographic features

In general, the cell type (e.g. serous, mucinous) often cannot be determined by the appearance on imaging . While some of the specific features can vary between the subtypes, there are certain features which are more common among mucinous tumors:

  • often larger than their serous counterparts (on occasion they may be enormous)
  • tend to be more multilocular with small cystic components +/- honeycomb-like locules
  • calcification is comparatively rare and if present tends to be linear
  • usually unilateral
  • peritoneal carcinomatosis is less common compared with serous tumors
  • may have accompanying pseudomyxoma peritonei
MRI
  • T1
    • signal intensity of locules varies depending on the degree of mucin concentration
    • loculi with watery mucin have a lower signal intensity than loculi with thicker mucin
  • T2
    • the above-mentioned corresponding signal intensities are flipped so that loculi with watery mucin have a higher signal intensity and loculi with thicker mucin appear slightly hypointense
    • the combination of locules with different signal intensities may result in a "stained glass appearance"

Treatment and prognosis

Prognosis of mucinous tumors is highly dependent on the stage and histologic composition: see individual subtypes for further details. Primary treatment is surgical unless there is extra-ovarian disease .

Differential diagnosis

  • ovarian serous tumors
    • tend to be unilocular  
    • often smaller than mucinous tumors
    • more frequently bilateral  
    • calcifications (psammoma calcifications) 
  • hemorrhagic cyst
    • smaller
    • unilocular
    • resolves on a follow-up scan
  • endometrioma
    • high signal on T1 weighted images with T2 shading (signal characteristics typical of blood products)
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