OBJECTIVES: 1) To determine the accuracy rate of sentinel lymph node  biopsy  (SLNB)  by  comparing  frozen  section  (FS)  with permanent formalin processed specimen by hematoxylin and eosin (H&E) staining; 2) To correlate with axillary lymph node dissection (ALND) histopathology results for those with positive SLNB.
METHODS: This  was  a  retrospective  study  on  all  breast  cancer patients  who  underwent  SLNB  using  methylene  blue  dye.  The number of SLN harvested, number of lymph nodes confirmed on frozen section, frozen section result, number of SLN confirmed on paraffin block H&E, result of H&E. If frozen section of SLN was positive for metastasis, further data on the axillary lymph nodes harvested and its final H&E result were noted. The accuracy rate was determined.  Whenever a discordance of FS and H&E findings occurred, the interpreting pathologists were interviewed for the cause.
RESULTS: A total of 34 SLNB procedures were performed. There were 24 SLNBs that turned out negative on frozen section while 10 were positive for metastasis and underwent further ALND. Three of the 24 negative SLNBs turned out to be positive (false negative rate of 12.5%). Out of the 10 positive SLNBs, 1 turned out to be negative (false positive rate of 10%). Only 6 of the 10 patients with (+) SLNB had  more  positive  nodes  harvested  upon  further  ALND.The accuracy rate of SLNB on frozen section was 88%, with sensitivity and  specificity  of  90%  and  87.5%  respectively.  There  were  5 pathologists involved in the interpretations of the SLNB, and in 76% the  pathologist  interpreting  the  FS  was  different  from  the  one interpreting  the  permanent  specimen  H&E.  The  reasons  for discordance between frozen section and final H&E reading were inter-reader variability and tissue sampling limitation during frozen section.
CONCLUSION: The accuracy of frozen section in SLNB procedure is 88%.

Human ; Sentinel Lymph Node Biopsy ; Hematoxylin ; Methylene Blue ; Formaldehyde ; Lymph Nodes ; Axilla ; Lymph Node Excision ; Breast Neoplasms