Detection of Adenocarcinoma In Situ of the Cervix in Papanicolaou Tests: Comparison of Diagnostic Accuracy With Other High-Grade Lesions

Abstract

Abstract Context.—Adenocarcinoma in situ of the cervix is a recently recognized interpretation in the Bethesda 2001 system. Although specific morphologic criteria have been published, recognizing this entity is still difficult. Objective.—To compare pathologists' ability to correctly identify and categorize adenocarcinoma in situ with their ability to identify and categorize adenocarcinoma, high-grade squamous intraepithelial lesion, and squamous cell carcinoma. Design.—Pathologists' reviews in the 2001 and 2002 College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology Program, an interlaboratory comparison program for gynecologic cytology, were examined. Cases were usually reviewed by multiple pathologists. False-negative rates, the percentage of reviews with exact agreement with reference interpretations, and the percentage of cases in which all reviews were in exact agreement with the reference interpretation for adenocarcinoma in situ, adenocarcinoma, high-grade squamous intraepithelial lesion, and squamous cell carcinoma were compared. Results.—A total of 213 reviews of cases categorized as adenocarcinoma in situ were compared with 2821 reviews of adenocarcinoma, 7535 reviews of high-grade squamous intraepithelial lesion, and 1886 reviews of squamous cell carcinoma. The false-negative rate for adenocarcinoma in situ (11.7%) was significantly higher than that for high-grade squamous intraepithelial lesion (4.6%, P < .001) and squamous cell carcinoma (3.3%, P < .001) but not for adenocarcinoma (8.9%, P = .16). Of all the reviews of adenocarcinoma in situ cases, 46.5% were interpreted specifically as adenocarcinoma in situ, compared to 72.2% of reviews of adenocarcinoma, 73.2% of high-grade squamous intraepithelial lesion, and 75.1% of squamous cell carcinoma. No individual case of adenocarcinoma in situ was always specifically recognized as adenocarcinoma in situ; 26.5% of cases of adenocarcinoma were specifically recognized as such in all reviews. Findings were similar with and without the inclusion of high-grade squamous intraepithelial lesion/carcinoma, not otherwise specified, as an acceptable review interpretation for cases of adenocarcinoma, squamous cell carcinoma, and high-grade squamous intraepithelial lesion. Conclusion.—These data from expert-referenced and biopsy-proven cases suggest that adenocarcinoma in situ is not as easily recognized or categorized as other serious diagnoses.