title: Synchronous Ovarian and Appendiceal Mucinous Neoplasms in the Absence of Pseudomyxoma Peritonei.
abstract: Synchronous ovarian/appendiceal mucinous neoplasms sometimes occur in the absence of clinical pseudomyxoma peritonei (PMP), which raises a question about whether the 2 tumors could be independent.
  
  
  
  We identified 11 cases of synchronous ovarian/appendiceal mucinous neoplasms without PMP and subclassified them into groups 1 and 2 based on the presence or absence of microscopic peritoneal/ovarian surface mucin deposits. A 7-marker panel (CK7, CK20, CDX2, PAX8, MUC1, MUC2, and MUC5AC) immunohistochemistry was performed on both tumors.
  
  
  
  Between the 2 groups, there were no significant differences in age, laterality, size, and histology of ovarian/appendiceal tumors. In group 1, 2 of 4 cases developed PMP later, and both had ovarian surface and contralateral ovarian involvement and appendiceal perforation with microscopic mucin deposits on the peritoneum. No patients in group 2 developed PMP. All group 1 cases showed a high degree of concordance of immunoprofile between the synchronous tumors, with an identical expression of appendiceal pattern in greater than 90% of the markers. In group 2, only 1 of 7 cases showed concordance in all markers.
  
  
  
  If peritoneal mucin deposits present, even microscopic and acellular, the synchronous tumors are most likely of a single appendiceal origin. Otherwise, they are more heterogeneous, and some may be truly dual primaries.
authors.affiliation: *Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary; and †Calgary Laboratory Services, Calgary; and ‡Department of Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Xianyong
authors.initials: X
authors.lastname: Gui
authors.forename: Jorge
authors.initials: J
authors.lastname: Escobar
authors.forename: Cheng-Han
authors.initials: CH
authors.lastname: Lee
authors.forename: Máire A
authors.initials: MA
authors.lastname: Duggan
authors.forename: Martin
authors.initials: M
authors.lastname: Köbel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D014408:Biomarkers, Tumor / Q000378:metabolism*; D000071616:CDX2 Transcription Factor / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053554:Keratin-20 / Q000378:metabolism; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D000072636:PAX8 Transcription Factor / Q000378:metabolism; D011553:Pseudomyxoma Peritonei / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; C507499:KRT20 protein, human; D053554:Keratin-20; D009077:Mucins; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human