Only a small fraction of high-grade cervical lesions are discovered after an interpretation of atypical squamous cells of undetermined significance when using imager-assisted, liquid-based Papanicolaou tests and the Bethesda 2001 system

Context. - Previous work has reported that most high-grade cervical neoplasia is seen in patients with preceding Papanicolaou test results of atypical squamous cells of undetermined significance. This information was based on conventional test results and the Bethesda 1991 reporting system and was determined before the current treatment guidelines. Objective. - Our objective was to perform a retrospective review of all histologically confirmed, high-grade cervical neoplasia to determine the diagnosis of the preceding liquid-based Papanicolaou test. Design. - A total of 189 histologically confirmed, highgrade cervical intraepithelial neoplasia (CIN) cases grade 2 and greater were identified for a 1-year period. Results. - Of the 189 cases, 10 (5.3%) had a previous diagnosis of atypical squamous cells of undetermined significance; 55 (29.1%) had low-grade squamous intraepithelial lesions; 31 (16.4%) had low-grade squamous intraepithelial lesions, unable to rule out a high-grade squamous intraepithelial lesion; 21 (11.1%) had atypical squamous cells, unable to rule out a high-grade squamous intraepithelial lesion; 68 (36%) had high-grade squamous intraepithelial lesions; 1 (0.5%) had atypical glandular cells; 1 (0.5%) had adenocarcinoma in situ; and 2 (1%) had invasive carcinoma. Combined "low grade" Papanicolaou test results (atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion) preceded 51 of 103 cases of CIN 2 (49.5%) and 14 of 103 cases (13.6%) of CIN 3/cancer, whereas "high grade" Papanicolaou test results (atypical squamous cells, unable to rule out a high-grade squamous intraepithelial lesion; low-grade squamous intraepithelial lesions, unable to rule out a high-grade squamous intraepithelial lesion; high-grade squamous intraepithelial lesions; atypical glandular cells; adenocarcinoma in situ; and invasive carcinoma) preceded 52 of 103 CIN 2 cases (50.5%) and 72 of 103 CIN 3/cancer cases (69.9%). Conclusions. - Our data show that we can now morereliably predict high-grade dysplasia on routine Papanicolaou tests. Only a small fraction of histologically confirmed CIN 2/3 cases are found following a Papanicolaou test diagnosis of atypical squamous cells of undetermined significance.