An Update on Glacial Acetic Acid Use and Atypical Endocervical and Glandular Cells

Summary: Introduction: Glacial acetic acid (GAA) is used to treat ThinPrep Papanicolaou tests with excess blood that would otherwise be unsatisfactory for diagnosis. More atypical appearance of endocervical glandular cells can be associated with GAA use. Some studies indicate treatment with GAA increases false-positive interpretations of atypical endocervical cells. Materials and Methods: Papanicolaou specimens from a tertiary medical center were analyzed retrospectively over a five-year period. Samples treated with GAA with positive cytologic findings (ASC-US or worse) were included. Rates of atypical endocervical cells (AEC) and atypical glandular cells (AGC) in GAA-treated and untreated samples were calculated. Chart review of GAA-treated cases with positive cytologic findings was undertaken and diagnoses were standardized. Surgical follow-up within one year was categorized as escalation from cytologic diagnosis for higher-grade lesions, or as de-escalation for lower. Results: From 258,185 untreated Papanicolaou tests, 41,041 had at least one positive cytologic diagnosis (17.06%). There were 7,004 cases treated with GAA, of which 964 had positive cytologic diagnoses (13.76%). AEC interpretations were present in 34 (0.49%) GAA-treated samples and in 417 (0.16%) GAA-untreated. For cases with either AEC or AGC interpretations, 66 (0.94%) were found on GAA-treated samples and 502 (0.19%) on GAA-untreated. Follow-up surgical pathology demonstrated escalation from an AEC interpretation in 18.75% of cases treated with GAA, while 81.25% were de-escalated. In treated cases initially called AGC, 54.55% were escalated and 45.45% de-escalated. When initial AEC and AGC cases were considered together, 45% escalated to a higher lesion on follow up. Conclusions: Like previous studies, our data indicates AEC/AGC interpretations are more frequent on samples treated with GAA. However, this analysis indicates GAA-treated samples with AEC/AGC interpretations were split almost evenly between escalated and deescalated lesions. Additional statistical analysis is being pursued to determine the distinction between these results and surgical follow-up for non-GAA treated lesions.