[478] Over-Interpretation of Liquid-Based Pap Tests Due to Cervical Endometriosis: A Diagnostic Pitfall

Y Wang, RA Goulart, DC Chhieng. Baystate Medical Center/Tufts University School of Medicine, Springfield, MA; Yale-New Haven Hospital/Yale University, New Haven, CT

Background: Endometriosis of the cervix is a potential pitfall for the over-interpretation of cervico-vaginal Pap tests. This is further complicated by the variable morphologic features of cervical endometriosis, which are dependent on the patient hormonal status and menstrual cycle. The varied cytologic features overlap with both those of atypical glandular cells and atypical squamous cells. As such, erroneous Pap test interpretations may range from atypical glandular cells (AGC) and atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H) to high grade squamous intraepithelial lesion (HSIL) and endocervical adenocarcinoma in-situ. The goal of this study was to examine the impact of biopsy-confirmed cervical endometriosis on the interpretation of the previous abnormal Pap test, in a large cytopathology laboratory.
Design: The Pathology computer files at our hospital were searched from 2004 to 2009 for patients with benign cervical tissue specimens containing endometriosis, which were preceded by abnormal Pap test results. HPV DNA test results, when performed, were recorded. All Pap tests were processed as ThinPrep, with HPV DNA testing performed by Qiagen HCII.
Results: Five patients were identified, ranging in age from 27 to 52 (mean 36). The prior Pap test diagnoses were: ASC-H (two cases), LSIL (two cases) and one case of AGC, favor neoplasia, which led to hysterectomy. Two patients underwent LEEP cone biopsy, one patient underwent cold-knife conization, and one patient had multiple cervical colposcopic biopsies. Histologically, four cases contained focal cervical endometriosis, with extensive endometriosis present in the remainder. No specimens contained evidence of either a squamous intraepithelial lesion or endocervical adenocarcinoma. HPV DNA testing was negative in four of the five patients.
Conclusions: Cervical endometriosis remains a cause of Pap test over-interpretation in a small but definite subset of patients. It is important to examine colposcopic/conization biopsies for this entity, particularly when dysplasia is not identified and HPV DNA testing is negative.
Category: Cytopathology

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 77, Tuesday Morning


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