title: Adult embryonal rhabdomyosarcoma metastatic to the breast and diagnosed by fine needle aspiration. A case report.
abstract: BACKGROUND
  Metastasis to the breast from extra-mammary malignancies is rare, but its recognition is important. A solitary metastasis must be distinguished from the primary breast cancer because the treatment and prognosis are quite different.
  
  
  METHODS
  A 30-year-old female presented with a 4.0-cm, solitary, nontender mass in the upper outer quadrant of the right breast 11 months after primary surgery for maxillary sinus embryonal rhabdomyosarcoma. The cytomorphology revealed features of small round cell tumor. Immunocytochemical staining disclosed a positive reaction to vimentin and desmin and negative reaction to cytokeratin, confirming the diagnosis of rhabdomyosarcoma.
  
  
  CONCLUSIONS
  Fine needle aspiration with ancillary studies is essential in the diagnosis of metastatic malignancy of the breast in order to avoid unnecessary mastectomy and to implement appropriate systemic therapy.
authors.affiliation: Department of Pathology, Veterans General Hospital-Taipei, Taiwan, Republic of China.
authors.forename: C R
authors.initials: CR
authors.lastname: Lai
authors.forename: C Y
authors.initials: CY
authors.lastname: Hsu
authors.forename: S H
authors.initials: SH
authors.lastname: Tsay
authors.lastname: Hung-Chiang
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000556:secondary*; D003893:Desmin / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008444:Maxillary Sinus Neoplasms / Q000473:pathology; D018233:Rhabdomyosarcoma, Embryonal / Q000737:chemistry / Q000175:diagnosis* / Q000556:secondary*
chemical_list: D003893:Desmin