Retrospective Rescreening of Negative Cervical Cytology Samples Preceding Histologically Proven CIN2-3 and Squamous Cell Carcinoma: An Educational Opportunity to Understand and Prevent Laboratory Errors.
OBJECTIVE
We aimed to analyze the false-negative (FN) liquid-based cytology diagnoses from the 5 years preceding all the 2013 histologically proven cervical intraepithelial neoplasia (CIN)2-3 and squamous cell carcinoma (SCC) and to propose corrective actions.


METHODS
This was a retrospective, blinded rescreening ('5-year look-back') of liquid-based cytology samples with negative categorizations, which occurred before histologically proven CIN2-3 and SCC.


RESULTS
The FN rate was 7.8% (21/256 samples preceding CIN2-3 and 0/13 samples preceding SCC). Slides confirmed as 'negative', 'interpretation error' and 'screening error', respectively, were 3.3% (9/269), 2.6% (7/269) and 1.9% (5/269). In 9/12 cases, error was associated with small atypical cells. In 7/12 cases, these diagnostic cells were less than 5/10 HPF. Inflammation and prominent reactive changes were present in 5/12 cases. Five patients had a positive clinical history. In 2 cases, there were multiple-cell-layer artifacts. Dense groups of small blue atypical cells were missed in 2 other cases. Dotting was imprecise in 6/7 samples.


CONCLUSIONS
Considering the above results, we specifically reoriented our continuous education activities, focusing rapid rescreening on scanty, isolated, small, atypical cells and dense cell groups. Prior to final diagnosis, pathologists should systematically review the entire surface of the dotted slides, with special attention being devoted to slides with multiple cell layers and tridimensional groups.
Anatomic Pathology Laboratory, Institut Bordet, Universitx00E9; Libre de Bruxelles, Brussels, Belgium.
Francesco
F
Feoli
Christine
C
Renard
Meryme
M
Abouyahia
Roland
R
De Wind
Denis
D
Larsimont
Marc
M
Arbyn
D000328:Adult; D003581:Cytodiagnosis / Q000592:standards*; D003951:Diagnostic Errors / Q000517:prevention & control*; D005188:False Negative Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007753:Laboratories / Q000592:standards*; D008403:Mass Screening; D009367:Neoplasm Staging; D018307:Neoplasms, Squamous Cell / Q000175:diagnosis*; D011379:Prognosis; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis*; D014626:Vaginal Smears; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis*