title: The association of cytokeratin-only-positive sentinel lymph nodes and subsequent metastases in breast cancer.
abstract: BACKGROUND
  The purpose of this study was to better characterize the clinical significance of cytokeratin immunohistochemistry (IHC)-only-positive lymph node metastases among patients with breast cancer.
  
  
  METHODS
  We performed a retrospective review of 334 patients who underwent sentinel lymph node (SLN) biopsy from 1 February 1997 through 31 July 2001. SLN biopsies were evaluated using standard hematoxylin and eosin (H&E) techniques. If H&E was negative, cytokeratin IHC was performed. We then evaluated the incidence of subsequent regional and distant metastatic disease.
  
  
  RESULTS
  Cytokeratin IHC was performed on 183 sentinel node biopsies from 180 patients comprising a total of 427 sentinel lymph nodes. The procedures included lumpectomy and SLN biopsy (n = 83), mastectomy with SLN biopsy (n = 7), lumpectomy with SLN biopsy and completion axillary dissection (n = 80), and modified radical mastectomy with SLN biopsy and completion axillary dissection (n = 13). Cytokeratin IHC was negative in 175 axillary specimens and positive in 8 (4.4%) from 8 different patients. In these eight specimens, deeper sections with subsequent H&E staining additionally identified micrometastasis in four patients. Three of these 8 patients (37.5%) developed distant metastatic disease compared with 1 of the 172 patients (0.6%) with negative cytokeratin IHC (P < .001). Additionally, one of the cytokeratin-positive patients developed regional nodal metastasis compared with none of the 172 cytokeratin-negative patients.
  
  
  CONCLUSIONS
  Cytokeratin IHC provides a clinically relevant adjunct to H&E staining for evaluating sentinel lymph nodes in breast cancer. These data suggest that patients with cytokeratin-positive sentinel nodes are at increased risk for development of regional and distant metastatic disease.
authors.affiliation: Department of Surgery, Madigan Army Medical Center, 9040A Reid Street, Tacoma, WA 98431, USA.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Mullenix
authors.forename: Tommy A
authors.initials: TA
authors.lastname: Brown
authors.forename: Micheal O
authors.initials: MO
authors.lastname: Meyers
authors.forename: Lydia R
authors.initials: LR
authors.lastname: Giles
authors.forename: Elin R
authors.initials: ER
authors.lastname: Sigurdson
authors.forename: Marcia C
authors.initials: MC
authors.lastname: Boraas
authors.forename: John P
authors.initials: JP
authors.lastname: Hoffman
authors.forename: Burton L
authors.initials: BL
authors.lastname: Eisenberg
authors.forename: Michael H
authors.initials: MH
authors.lastname: Torosian
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis*; D008207:Lymphatic Metastasis / Q000473:pathology*; D009367:Neoplasm Staging / Q000379:methods*; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy
chemical_list: D007633:Keratins