title: Melanoma metastatic to the breast: utility of fine needle aspiration and immunohistochemistry.
abstract: OBJECTIVE
  To describe the morphologic spectrum of metastatic malignant melanoma (MM) cells involving the breast and to explore the diagnostic utility of HMB45, Mart-1, Melan-A and T311 (antityrosinase) antibodies in fine needle aspiration material of MM metastatic to the breast.
  
  
  METHODS
  Cytologic material from 21 cases (18 women) was reviewed for cytomorphology (epithelioid, spindled, mixed) and immunocytochemical staining attributes for Mart-1, HMB45, T311, Melan-A and cytokeratin based on tissue availability.
  
  
  RESULTS
  Seventeen cases (81%) demonstrated epithelioid cell morphology, with 14% exhibiting mixed and 5% spindled morphologies. All 21 cases (100%) were immunoreactive with Mart-1 antibody, with 81% (17/21) immunoreactive for HMB45. In 38% of cases there was a similar percentage of cells immunoreactive for Mart-1 and HMB45, while 48% showed a higher percentage of cells immunoreactive for MART-1 than HMB45. Immunoreactivity with T311 was seen in 8 of 11 cases tested (73%). All six cases tested (100%) were immunoreactive with Melan-A. Staining for cytokeratin was negative in all eight cases tested.
  
  
  CONCLUSIONS
  Because the majority of MM metastatic to the breast shows epithelioid cell morphology, it may mimic primary breast carcinoma. Mart-1 should be part of the immunocytochemical panel utilized to confirm the diagnosis of MM metastatic to the breast.
authors.affiliation: Cytopathology Section, Laboratory of Pathology, National Cancer Institute, Bethesda, Maryland, USA.
authors.forename: Armando Carlos
authors.initials: AC
authors.lastname: Filie
authors.forename: Aylin
authors.initials: A
authors.lastname: Simsir
authors.forename: Patricia
authors.initials: P
authors.lastname: Fetsch
authors.forename: Andrea
authors.initials: A
authors.lastname: Abati
mesh_terms: D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000378:metabolism; D015415:Biomarkers; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000556:secondary*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D058965:MART-1 Antigen; D008545:Melanoma / Q000378:metabolism / Q000473:pathology* / Q000556:secondary*; D058950:Melanoma-Specific Antigens; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000473:pathology
chemical_list: D000951:Antigens, Neoplasm; D015415:Biomarkers; D058965:MART-1 Antigen; C548667:MLANA protein, human; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D007633:Keratins; D014442:Monophenol Monooxygenase