[1108] Low Grade Squamous Intraepithelial Lesion/Cannot Exclude High Grade Squamous Intraepithelial Lesion (LSIL-H): A Unique Cytologic Abnormality

Stacey Barron, Zaibo Li, R Marshall Austin, Chengquan Zhao. Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA

Background: SIL of Indeterminate Grade was introduced in the 2001 Bethesda system. This term, or low grade squamous intraepithelial lesion, cannot exclude high grade squamous intraepithelial lesion (LSIL-H), has been used. Data about prevalence of hrHPV in women with LSIL-H and subsequent histopathology are limited.
Design: A search of CoPath files was performed to retrieve cases with a cytologic diagnosis of LSIL-H and concurrent hrHPV testing between 07/2005 and 12/2011. HrHPV testing and histologic follow-up results were recorded.
Results: 495 cases with a cytologic diagnosis of LSIL-H and concurrent hrHPV testing were identified. HrHPV was positive in 448 of 495 cases (90.5%). Patients' average age was 30 years old (range: 15-80, median: 27). Of 347 patients who had at least one subsequent histologic follow-up within an average period of 24 months (range: 6-66, median: 24), CIN2/3 was detected in 103 patients (29.7%) and CIN1 in 186 patients (53.6%). Of those 103 cases with a histologic follow-up of CIN 2/3, the median interval between LSIL-H and initial CIN2/3 diagnosis was about 3 months (range: 0.5-60). CIN2/3 was identified on histopathologic follow-up in a significantly greater proportion of women with hrHPV-positive LSIL-H than patients with hrHPV-negative LSIL-H (p<0.05). The hrHPV positivity data and histopathologic follow-up data are also compared to our published data in patients with LSIL, ASC-H, and HSIL from the same institution (Table 1).

Table 1. Comparison of Rates of HPV Positivity and CINs Between LSIL-H and Other Cytologic Abnormalities
CategoryHPV Positive RateCIN2/3CIN1
LSIL-H90.5%99/321(30.8%)4/26 (15.4%)172/321 (53.6%)14/26 (53.8%)
HSIL95.7%197/273 (72.2%)4/12 (33.3%)52/273 (19.1%)5/12 (41.7%)
ASC-H54.3%84/257 (32.7%)3/248 (1.2%)76/257 (29.2%)32/248 (12.9%)
LSIL80.2%89/612 (14.5%)4/107 (3.7%)357/612 (58.3%)44/107 (41.1%)

Conclusions: HrHPV and histopathologic CIN2/3 detection rates with LSIL-H (90.5% and 29.7%) were significantly lower than in patients with HSIL (95.7% and 71.2%) and significantly higher than in patients with LSIL (80.2% and 13.1%) and with ASC-H (54.3% and 17.2%). Whereas histopathologic CIN2/3 detection rates were similar in LSIL-H as in ASC-H for HPV positive cases (30.8% vs 32.7%), the rate is higher in LSIL-H than in ASC-H for HPV negative cases (15.4% vs 1.2%). Our results suggest LSIL-H is a unique category of cytologic abnormality associated with distinctive hrHPV and CIN2/3 detection rates.
Category: Gynecologic & Obstetrics

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 182, Wednesday Afternoon


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