Evaluation of cellular adequacy in endometrial liquid-based cytology

Objective: This study evaluated cellular adequacy in endometrial liquid-based cytology (LBC) specimens.

Methods: In total, 1267 cases were obtained and the rate of unsatisfactory specimen and diagnostic accuracy for malignancy were assessed. If ≥10 cellular clusters composed of ≤30 endometrial cells were found per specimen, then the sample was provisionally considered adequate.

Results: The unsatisfactory rate (with fewer than 10 clusters) was 15.4%. Diagnostic accuracy in specimens with ≥10 clusters was significantly higher (90.5% vs 36.4%) than that in specimens with fewer than10 clusters. Moreover, the unsatisfactory rate in patients aged ≥60 years was significantly higher (33.8% vs 13.2%) than that in patients younger than 60 years. Although the unsatisfactory rate was decreased, significant differences were not found between cases with fewer than five clusters (22.6%) and fewer than 10 clusters (33.8%) in patients aged ≥60 years. Diagnostic accuracy in cases with five or more clusters was significantly higher (90.3% vs 0%) than that in cases with fewer than five clusters.

Conclusions: We propose that ≥10 clusters with ≥30 endometrial cells per cluster could be used as a specimen adequacy criterion for endometrial LBC. If ≥10 clusters cannot be found in patients aged ≥60 years, then the use of the alternative criterion of five or more clusters may yield satisfactory specimen adequacy.