Imprint cytology of sentinel lymph nodes in breast cancer. Experience with rapid, intraoperative diagnosis and primary screening by cytotechnologists.
OBJECTIVE
To evaluate the intraoperative imprint diagnoses of smears from sentinel lymph nodes that had been primary screened by cytotechnologists and to assess the most important causes of false negative (FN) imprint diagnoses.


METHODS
Material consisted of 429 imprints from sentinel lymph nodes in 211 breast cancer patients that were sent for frozen section examination over 13 months.


RESULTS
The mean number of imprints/lymph nodes per patient was 2.02. The mean screening time per imprint was 3.6 minutes. Sixty-six sentinel nodes (16%) from 51 women (24%) were metastatic. Imprints and/or frozen sections were positive in 54 nodes (82%). Imprints were positive in 38 nodes, representing 70% of intraoperative positive nodes and 58% of the total number of positive nodes. Twenty-six of 28 (93%) FN imprints were due to suboptimal sampling. Four of 9 FN macrometastases did not contain diagnostic or suspicious cells/cell groups even on rescreening, whereas a few, and then only 1 diagnostic group were identified in 2/9. There were no false positives.


CONCLUSIONS
Primary screening by experienced cytotechnologists is both rapid and reliable and enabled the diagnosing pathologist to concentrate on the frozen section. The major cause of false negative imprints is sampling, even in macrometastases.
Sauer
Torill
T
Department of Pathology, Ullevål University Hospital, N-0407 Oslo, Norway. torill.sauer@ulleval.no
Engh
Vibeke
V
Holck
Anne Marie
AM
Sørpebøl
Grete
G
Heim
Mette
M
Furu
Irene
I
Schlichting
Ellen
E
D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000556:secondary; D018275:Carcinoma, Lobular / Q000556:secondary; D003581:Cytodiagnosis / Q000379:methods; D005188:False Negative Reactions; D005260:Female; D005629:Frozen Sections; D006801:Humans; D007432:Intraoperative Period; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008403:Mass Screening; D009367:Neoplasm Staging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods