Accuracy of ThinPrep imaging system in detecting atypical glandular cells

The aim of this study was to evaluate the accuracy of the ThinPrep Imaging System (Imager) in detecting atypical glandular cells (AGC) or adenocarcinoma in the 22 selected fields. All cases reported as AGC or adenocarcinoma from January 2005 to December 2006 that had been initially screened by the Imager were retrospectively reviewed to determine whether the most diagnostically relevant groups/cells were within the 22 selected fields. A total of 39 cases were reviewed. The cases were divided into two groups: the group with diagnostic cells detected within the 22 selected fields (accurately detected group) and the group with upgraded diagnosis following rescreening process (underdetected group). The Imager accurately detected 32 (82%) of cases with abnormal glandular cells, including six cases reported as adenocarcinoma, one case as adenocarcinoma in situ (AIS), and 25 cases as AGC. In seven (18%) cases, the Imager failed to detect the most abnormal cells within the 22 selected fields. Among these, one case was adenocarcinoma, while the rest were reported as AGC. Overall, four cases were assessed as atypical during quality control (QC) rescreening even though the Imager detected abnormal groups in most. Fourteen of 32 cases had abnormalities proven by histologic follow-up. Overall, the Imager was effective in detecting most AGC, AIS and invasive adenocarcinomas. In a minority (18%) of cases, the Imager failed to detect the cells of interest within the 22 selected fields. However, full manual review of cases with potential atypical/reactive groups or endometrial groups in women ≥ 40 and QC rescreening of selected cases may help to minimize the underdetected cases.