False positive diagnosis in conventional and liquid-based cervical specimens

To examine conventional and liquid-based cervical smears falsely diagnosed as malignant at our institution and to investigate, through cytologic-histologic correlation, factors influencing false positive diagnoses. Cervical cytologic diagnoses of malignancy from May 1, 1995, to April 30, 2001, were retrieved through a computer search. A retrospective review of hospital records and pathology reports was performed. Cases identified as false positives were reviewed and correlated with histologic follow-up specimens. A group of 68 patients with malignancy reported on cervical smears and with histologic follow-up was identified. Conventional smears numbered 32 (47%); the remaining 36 (53%) were liquid-based samples. Of the total, 7 false positive cases (10.3%) were identified in 4 conventional and 3 liquid-based preparations. Cytologic diagnosis in these cases was squamous cell carcinoma in 5 and adenocarcinoma in 2. On histologic follow-up, all 7 patients were ultimately found to have high grade squamous intraepithelial lesions (HSILs) without invasion. Review of the original slides confirmed most, or all, of the following features in all cases: major cellular pleomorphism, extensive cytoplasmic keratinization, intense nuclear pykn...Continue Reading