Mucinous tumors
Mucinous borderline tumor / atypical proliferative mucinous tumor

Topic Completed: 1 July 2012

Minor changes: 22 January 2021

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PubMed Search: Ovarian mucinous borderline tumor

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Cite this page: Ehdaivand S. Mucinous borderline tumor / atypical proliferative mucinous tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumorborderlinemucinous.html. Accessed January 24th, 2021.
Definition / general
  • Also called atypical proliferative mucinous tumor of ovary or mucinous ovarian tumor of low malignant potential
  • 85% are intestinal type; 15% are seromucinous (endocervical) type
  • 5% of intestinal type are bilateral; 30 - 40% of seromucinous type are bilateral (Cancer 1988;61:340)
  • Pure borderline tumors and borderline tumors with intraepithelial carcinoma or microinvasion are almost always Stage I and clinically benign, but must sample tumor extensively to rule out more extensive invasion (Am J Surg Pathol 2002;26:139)
  • High stage borderline tumors with abdominal cavity mucin may represent ovarian metastases rather than primary borderline tumors - must examine appendix to correctly interpret
Clinical features
Intestinal type:
  • 85% of borderline mucinous cases
  • Older patients, not associated with endometriosis
  • Excellent prognosis
  • Intestinal type are further divided:
    • With atypia only
    • With intraepithelial carcinoma
    • With microinvasion

Seromucinous (endocervical) type:
  • 15% of borderline mucinous tumors
  • Tumors usually mixed but clinically resemble serous tumors due to papillary architecture, serous type differentiation, frequent bilaterality, smaller size, indolent clinical behavior (only rare deaths, Am J Surg Pathol 2002;26:1529)
  • Mean 39 years (younger patients), range 25 - 64 years
  • Associated with endometriosis in 41% of cases, endosalpingiosis in 32%
  • Malignancy is based on cytology, not number of cell layers
  • Almost always stage I, excellent prognosis with no evidence of disease at followup, even with intraepithelial carcinoma, microinvasion or extraovarian involvement (implants and lymph node involvement) (Am J Surg Pathol 2004;28:1311)
Prognostic factors
  • 10 year survival: stage I - 95% (better than previously thought; prior series may have included metastases from intestine and pancreas); noninvasive malignant - 90% (Am J Surg Pathol 2000;24:1447)
Gross images

AFIP images

Intestinal type:
mucinous cystic

Images hosted on other servers:

Intestinal type:
borderline tumor

Microscopic (histologic) description
  • Intestinal type:
    • With atypia only:
      • Resemble dysplastic intestinal epithelium with goblet cells, neuroendocrine cells and occasional Paneth cells
      • Neoplastic cells have hyperchromasia, crowding, increased mitosis, and stratification forming papillae with thin fibrous cores
      • Lumens contain mucin
    • With intraepithelial carcinoma:
      • Resemble high grade dysplasia of intestines with severe cytologic atypia without stroma invasion
      • Papillae without stroma and cribriforming is often present
    • With microinvasion:
      • Invasive foci measuring less than 10 mm2 and < 3 mm in greatest dimension
      • Foci of stromal invasion with desmoplastic response or small clusters of cells, occasionally cribriform with eosinophilic cytoplasm with minimal / absent stromal reaction (Hum Pathol 1996;27:521)
      • Desmoplastic stroma has pale nuclear staining, fibrous reaction or edema in stroma
      • Areas of mucin extravasation with inflammatory response are not diagnostic of invasion; this includes a brisk inflammatory reaction with histocytes and large areas of necrosis

  • Seromucinous (endocervical) type:
    • Proliferation of branching papillary structures resembling borderline serous tumors
    • Papillae composed of fibrovascular cores of variable size covered by variable epithelium including mucinous or eosinophilic cells
    • Mucinous cells have basal nuclei
    • Some papillary tips lack fibrovascular cores
    • Small detached clusters of cells may be observed over the papillary tufts
    • Hobnail cells also present
    • Rare intraepithelial carcinoma or stromal microinvasion but no stromal invasion
    • Associated with invasive or noninvasive desmoplastic implants

  • Classification:
    1. Borderline with atypia: grade 1 nuclei and papillae with cords
    2. Borderline with intraepithelial carcinoma: grade 2/3 nuclei, 4+ layers or cribriform or stroma-free papillary growth pattern
    3. Borderline with microinvasion: invasive glands usually accompanied by desmoplastic reaction
Microscopic (histologic) images

AFIP images

Mucinous cystic tumor with intraepithelial carcinoma

Intestinal type:
mucinous cystic tumor

Seromucinous (endocervical) type:

Mucinous cystic tumor

Mixed epithelial types

Omental implant

Molecular / cytogenetics description
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