[408] Atypical Squamous Cells of Undetermined Significance (ASC-US) Associated with Atrophy in Liquid-Based (Surepath) Pap Tests: Prevalence of Human Papillomavirus Infections and Follow-Up Biopsy Diagnoses

Andrew C Nelson, Tetyana N Mettler, Jana L Holler, Samy A Amirouche, Stefan E Pambuccian. University of Minnesota Medical Center, Fairview, Minneapolis, MN

Background: Despite its use for more than two decades and the clearly formulated Bethesda system diagnostic criteria, the diagnosis of atypical squamous cells of undetermined significance is still the most challenging and least reproducible diagnosis made on Pap tests. The diagnostic challenges are greatly exaggerated by the presence of atrophic changes (ATR) in the Pap test. The aim of this study was to determine the human papillomavirus (HPV) and follow-up biopsy correlates on ASC-US+ATR.
Design: We identified all cases diagnosed from 1/1/2003 to 12/31/2010 as ASC-US with concomitant atrophic changes (ASC-US+ATR) that had reflex HPV testing performed by a PCR-based method using MY09/11 consensus primers and typing by RFLP. All cases were diagnosed by 2001 Bethesda System criteria on Surepath Pap tests. The prevalence of any HPV type, high-risk HPV types (HR-HPV) and HPV16/18 and the frequency of abnormal follow-up biopsies diagnosed as CIN1 and above (CIN1+) and CIN2 and above (CIN2+) was compared statistically to those of all other cases of ASC-diagnosed within the same interval.
Results: Of the 23077 cases diagnosed as ASC-US during the study interval, 284 (1.23%) were associated with ATR.

ALL ASC-US (N=23077)36.3+/-13.28937 (38.7%)4277 (18.5%)1993 (8.6%)4241 (18.4%)1845 (8%)581 (2.52%)
ASC-US+ATR (N=284)59.4+/-10.439 (13.7%)17 (6%)3 (1.1%)22 (7.8%)5 (1.8%)2 (0.7%)
ASC-US+ATR VS. ALL ASC-US %CHANGE -125%-67.7%-87.8%-57.9%-106.2%-101.8%
ASC-US+ATR VS. ALL ASC-US p VALUE<0.0001<0.0001<0.0001<0.0001<0.0001<0.0001NS (0.053)

Women with ASC-US+ATR were significantly older than women with ASC-US without atrophy. However, the differences in prevalence of HPV, HR-HPV, HPV16/18 and of CIN1+ and CIN2+ diagnoses persisted even when the results were analyzed by age groups.
Conclusions: In our institution, ASC-US+ATR constitues a small fraction of ASC-US diagnoses.
We found profoundly and significantly lower HPV rates and follow-up abnormal biopsy diagnoses in women with ASC-US+ATR as compared to all women with a diagnosis of ASC-US.
Our data suggest that better criteria are needed to differentiate between atrophic changes and clinically significant squamous atypia in Pap tests.
Category: Cytopathology

Tuesday, March 20, 2012 2:15 PM

Platform Session: Section C, Tuesday Afternoon


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