title: An immunohistochemical study of morules in endometrioid lesions of the female genital tract: CD10 is a characteristic marker of morular metaplasia.
abstract: OBJECTIVE
  To analyze immunohistochemically morules in endometrioid lesions to show that CD10 is a sensitive marker for morular metaplasia.
  
  
  METHODS
  Immunohistochemical analysis of 53 instances of morular metaplasia comprising 1 cyclic endometrium and 52 endometrioid lesions associated with focal glandular complexity corresponding to 9 polyps, 4 atypical polypoid adenomyomas, 24 complex endometrial hyperplasias (18 with and 6 without atypia), 12 grade 1 endometrioid adenocarcinomas in early clinical stages of both uterus and ovary, and three ovarian adenofibromas. Immunohistochemistry in paraffin sections was done for CD10, beta-catenin, estrogen and progesterone receptors, and cytokeratins 5-6, 7, 8, 13, 18, 19, 20, and 34beta-E12.
  
  
  RESULTS
  Morules were negative for estrogen and progesterone receptors and had beta-catenin-positive nuclei. Cytokeratins 8, 18, 19 were positive; cytokeratins 7 and 20 were negative; and cytokeratins 5-6, 13, and 34beta-E12 were weakly positive. All cases revealed strongly positive membranous CD10 staining in morules, which was absent in glands. CD10 positivity allowed easy identification of morules at low power in various types of surgical specimens and in curettings. CD10 also highlighted early morular metaplasia in glandular epithelium. In cases associated with squamous, keratinizing metaplasia, CD10 discriminated between both types of metaplasia.
  
  
  CONCLUSIONS
  CD10 staining represents a useful marker of morules in endometrioid neoplasms of the female genital tract, permitting identification of lesions usually associated with an attenuated malignancy. Considering the immunohistochemical and genetic similarities of morules in tumors of different organs, it is likely that this marker may be also useful to diagnose morular metaplasia in similar neoplasms of extragenital locations.
authors.affiliation: Department of Oncological and Surgical Sciences (Pathology), Università degli Studi di Padova, Padova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Chiarelli
authors.forename: Catalina
authors.initials: C
authors.lastname: Buriticá
authors.forename: Piero
authors.initials: P
authors.lastname: Litta
authors.forename: Susana
authors.initials: S
authors.lastname: Ciani
authors.forename: Rosa
authors.initials: R
authors.lastname: Guarch
authors.forename: Francisco F
authors.initials: FF
authors.lastname: Nogales
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D016889:Endometrial Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D015260:Neprilysin / Q000096:biosynthesis*; D010053:Ovary / Q000378:metabolism; D014599:Uterus / Q000378:metabolism
chemical_list: D015260:Neprilysin