Cytokeratin immunostaining patterns of benign, reactive lymph nodes: applications for the evaluation of sentinel lymph node specimen

Appl Immunohistochem Mol Morphol. 2001 Dec;9(4):297-301. doi: 10.1097/00129039-200112000-00002.

Abstract

The use and interpretation of cytokeratin (CK) immunostains of sentinel lymph node specimens for breast carcinoma remain controversial. Variable immunoreactivity with anti-CK antibodies and CK-positive interstitial reticulum cells may complicate interpretation. The authors examined a series of reactive lymph nodes selected from patients without a history of malignancy. To demonstrate potential diagnostic pitfalls, three different CK antibody combinations were studied to characterize the immunostaining patterns. Formalin-fixed sections of lymph nodes were immunostained with a labeled streptavidin-biotin method using a DAKO autostainer. The anti-CK antibody preparations evaluated were AE1/AE3, CAM 5.2, and an in-house-prepared CK cocktail composed of 7 antibodies. The authors observed that up to 10% of cells in benign, reactive lymph nodes may be immunoreactive with anti-CK antibodies. AE1/AE3 stained 2 of 20 cases with rare immunoreactive reticulum cells, whereas CAM 5.2 and the CK cocktail immunostained cells in 85% of cases with reticulum cells in sinuses and the paracortex. Rare positive to 2+ cells were present in a similar distribution with these two antibodies. Careful interpretation of CK immunostaining of sentinel lymph node biopsies is essential, as is awareness of the presence of CK-positive native reticulum cells, to avoid confusion with single cells of metastatic carcinoma.

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Monoclonal
  • Child
  • Child, Preschool
  • Diagnostic Errors / prevention & control
  • Female
  • Humans
  • Immunohistochemistry
  • Keratins / immunology
  • Keratins / metabolism*
  • Lymph Nodes / chemistry
  • Lymph Nodes / pathology
  • Male
  • Pseudolymphoma / diagnosis*
  • Pseudolymphoma / metabolism
  • Pseudolymphoma / pathology
  • Sentinel Lymph Node Biopsy / methods
  • Sentinel Lymph Node Biopsy / standards*

Substances

  • Antibodies, Monoclonal
  • Keratins