False-negative Papanicolaou tests in women with biopsy-proven invasive endocervical adenocarcinoma/adenocarcinoma in situ: a retrospective analysis with assessment of interobserver agreement

•Endocervical glandular neoplasia (invasive endocervical adenocarcinoma [EA], adenocarcinoma in situ [AIS]) is difficult to detect on Pap tests and represents a common source of false-negative diagnoses and interobserver discordance in cervical cytology.•In this study, we conducted a retrospective review of false-negative Pap tests from patients with biopsy-proven EA/AIS and found that sampling and interpretive variance each accounted for nearly half of false-negative diagnoses.•Common sources of interpretive variance included misclassification of neoplastic glandular cells as reactive glandular cells or endometrial cells.•Targeted educational efforts resulted in a significant decrease in interpretive variance and interobserver discordance in diagnosis of glandular neoplasia in these false-negative cases.