The Value of a Duplicate Pap Smear Slide in Interpreting Atypical Squamous Cells, Cannot Exclude High-Grade Squamous Intraepithelial Lesion (ASC-H)
B Kelly, E Hospodar, S Zhang, F Abreo, J Thomas, J Bagby. LSUHSC-Shreveport, Shreveport, LA
Background: The category of ASC-H was added to the Bethesda system in 2001, which accounts for a small percentage of abnormal Pap smears. The ASC-H ratio is around 0.2-0.6% nationally and 0.4% in our laboratory. ASC-H encompasses a heterogeneous group of lesions including definite high-grade squamous intraepithelial lesion (HSIL), reactive metaplasia and benign hyperchromatic crowded groups. ASC-H comprises a higher number of high-grade lesions (30%-50%) compared to ASC-US (10%-15%). The treatment guidelines and follow-up procedures are different for HSIL, ASC-H and ASC-US; and a definitive diagnosis is crucial for proper clinical follow-up and treatment. This study aims to determine the role of evaluating duplicate slides in assessing ASC-H cases.
Design: 41 consecutive ASC-H cases were evaluated from October 2007 to March 2008. A duplicate Pap smear slide (DS) was prepared for each case. All DS were then reviewed blindly by a cytopathologist followed by a review of the corresponding histology. The DS were determined to be of value if HSIL or LSIL cells were identified upon review.
Results: 41 ASC-H DS were reviewed. Of these, 16 cases were diagnosed as HSIL or LSIL (13 HSIL, 2 LSIL vs. ASC-H, and 1 LSIL), 14 cases as ASC-H, 6 cases as ASC-US, and 4 cases as NILM. Therefore, reviewing DS potentially altered 16 ASC-H diagnoses to a more definitive interpretation. A total of 19 cases (19/41, 46.3%) had cervical biopsy follow-up, which revealed 10 cases of CIN2-3 (52.6%), 6 cases of CIN1 (31.6%), and 3 negatives (15.8%). Excluding the results of the DS review, the CIN 2-3 rate on ASC-H would only be 33.3%. 10 of the 16 cases with discrepancy had biopsy follow-up. 8 HSIL cases showed CIN 2-3 (6), CIN 1 (1), and negative (1); 1 LSIL vs. ASC-H case showed CIN 3; and 1 LSIL case showed CIN 1.
Conclusions: This study demonstrates that DS are very useful in evaluating ASC-H cases. Additional Pap smear material on the DS could substantially change the initial ASC-H diagnosis to HSIL or LSIL (39%); a change that would substantially alter patient management and clinical follow-up. HPV testing and p16INK4a immunohistochemistry have had some success in further classifying definite dysplastic cells and distinguishing reactive cells from ASC-H. However, these methods are not as cost effective as preparing a DS. Therefore, the value of DS should not be underestimated, and we highly recommend routine preparation and review of a DS before definitive interpretation of an ASC-H case.
Tuesday, March 23, 2010 9:30 AM
Poster Session III # 69, Tuesday Morning