title: Metaplastic carcinoma of the breast: an immunohistochemical study.
abstract: BACKGROUND
  Metaplastic breast carcinoma is a rare entity of breast cancer expressing epithelial and/or mesenchymal tissue within the same tumor. The aim of this study is to evaluate the clinicopathological features of metaplastic breast carcinoma and to confirm the triple negative, basal-like and/or luminal phenotype of this type of tumor by using immunohistochemical staining.
  
  
  METHODS
  Seven cases of MBC were evaluated for clinico-pathological features including follow up data. Cases were studied immunohistochemically by CK-Pan, Vimentin, ER, PR, HER2, basal markers (CK5/6, p63, EGFR, SMA and S-100), luminal cytokeratins (CK8, CK18 and CK19), markers for syncytial cells (β-HCG and PLAP), as well as prognostic markers (p53, ki-67 and calretinin).
  
  
  RESULTS
  The mean age of the patients was 36 years. Three cases showed choriocarcinomatous features. All of our cases were negative for ER, PR and HER2. Six out of the 7 cases showed basal-like differentiation by demonstrating positivity with at least one of the basal/myoepithelial markers. Also 6 out of the 7 cases expressed luminal type cytokeratins (CK8, CK18 and/or CK19). P53 was positive in 3 cases, ki-67 was strongly expressed in only one case, while calretinin was expressed in 6 cases.
  
  
  CONCLUSIONS
  Metaplastic breast carcinoma presents in our population at a younger age group than other international studies. All cases are categorized immunohistochemically under the triple negative group of breast cancer and 86% of them exhibited basal-like and luminal phenotype. Majority of cases developed local recurrence and distant metastasis in a relatively short period of time.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1101289295115804.
authors.affiliation: Pathology Department and General Surgery Department, Faculty of Medicine, King Abdulaziz University (KAU), P,O, Box 51241, Jeddah 21543, Saudi Arabia. fjaltaf@yahoo.com.
authors.forename: Fadwa J
authors.initials: FJ
authors.lastname: Altaf
authors.forename: Ghadeer A
authors.initials: GA
authors.lastname: Mokhtar
authors.forename: Eman
authors.initials: E
authors.lastname: Emam
authors.forename: Rana Y
authors.initials: RY
authors.lastname: Bokhary
authors.forename: Najlaa Bin
authors.initials: NB
authors.lastname: Mahfouz
authors.forename: Samia
authors.initials: S
authors.lastname: Al Amoudi
authors.forename: Zuhoor K
authors.initials: ZK
authors.lastname: Al-Gaithy
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor