Previous studies have suggested that cases of high-grade squamous intraepithelial lesion in conventional smears and in ThinPrep specimens that are frequently misinterpreted as normal have relatively few small and hypochromatic dysplastic cells.
To determine the cytologic differences between conventional Papanicolaou slides of high-grade squamous intraepithelial lesion that perform poorly and those that perform well.
We compared the cytologic features of 22 cases of conventional smears with high-grade squamous intraepithelial lesion that performed poorly in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology with 45 cases of conventional smears that performed extremely well.
Cases that performed poorly were significantly more likely to have 50 or fewer single dysplastic cells (P = .003) and to have only small dysplastic cells (P = .01). Cases that performed well were also more likely to have more than 500 dysplastic cells (P = .002), to exhibit the presence of large dysplastic cells (P < .001), and to be keratinized (P = .03). Hypochromasia and the number of groups of dysplastic cells were not correlated with performance.
Conventional smears with high-grade squamous intraepithelial lesion with 50 or fewer single dysplastic cells, no large dysplastic cells, and lacking keratinization are highly associated with poor performance in this program.