Intraoperative touch imprint cytological analysis of sentinel lymph nodes for the presence of metastases in breast cancer.

Background: Imprint cytology may provide a fast and accurate method for intraoperative screening of sentinel lymph nodes, so a decision can be made regarding whether to perform axillary clearance during primary surgery. If the findings are negative, in many cases axillary dissection can be omitted.

Methods: 128 sentinel nodes from a cohort of 87 patients that had been identified using technetium-99m nanocolloid as a radioactive tracer and Patent blue dye were dissected for rapid Diff-Quick stained touch preparations. Intraoperative evaluation of sentinel node status by imprint cytology was correlated with histopathological results of permanent sections. Tumor-negative nodes in routine paraffin sections were further investigated with the employment of an anti-cytokeratin antibody.

Results: 36 of all sentinel nodes harbored metastases in the paraffin sections, of which 32 were identified by imprint cytology (sensitivity 88.8%). 3 sentinel nodes were positive by imprint cytology and negative by histopathology of the paraffin sections. Comparison of the results of the touch preparations with the final histopathology (hematoxylin-eosin and anticytokeratin antibody stains) demonstrated a sensitivity of 83.3% and a negative predictive value of 92.5%. The specificity and positive predictive value were 100% each.

Conclusions: Touch imprint cytology is potentially useful for intraoperative evaluation of sentinel lymph nodes in breast cancer patients.